diff --git a/README.md b/README.md
index faccddf..9142703 100644
--- a/README.md
+++ b/README.md
@@ -82,21 +82,14 @@ echo $generator->everyFifteenMinutes(); // */15 * * * *
 echo $generator->everyThirtyMinutes(); // 0,30 * * * *
 
 // Every minute
-echo $generator->minutes('*'); // * * * * *
+echo $generator->set(new \Butschster\CronExpression\Parts\Minutes\EveryMinute()); // * * * * *
+echo $generator->set(new \Butschster\CronExpression\Parts\Minutes\EveryMinute(2)); // * */2 * * *
 
-// Every ten minutes
-echo $generator->minutes('*/10'); // */10 * * * *
-
-// Every hh:10, hh:11, ..., hh:30 minutes
-echo $generator->minutes('10-30'); // 10-30 * * * *
-
-// Hourly at hh:01
-echo $generator->minutes(1); // 1 * * * *
+// Specific minutes
+echo $generator->set(new \Butschster\CronExpression\Parts\Minutes\SpecificMinutes(2, 3, 10)); // * 2,3,10 * * *
 
-// Hourly at hh:05, hh:10, hh:15
-echo $generator->minutes(5, 10, 15, ...); // 5,10,15,... * * * *
-
-echo $generator->minutes(61); // Throws an exception: Invalid CRON field value 61 at position 0
+// Between minutes
+echo $generator->set(new \Butschster\CronExpression\Parts\Minutes\BetweenMinutes(0, 30)); // * 0-30 * * *
 ```
 
 ### Manipulate hours
@@ -122,13 +115,15 @@ echo $generator->everyFourHours(); // 0 */4 * * *
 // Every six hours
 echo $generator->everySixHours(); // 0 */6 * * *
 
-// Every 1, 2, 3 hours at 15 minutes
-echo $generator->hourlyAt(15)->hours(1, 2, 3); // 15 */3 * * *
+// Every 1, 2, 3 hours
+echo $generator->set(new \Butschster\CronExpression\Parts\Hours\SpecificHours(1, 2, 3)); // * 1,2,3 * * *
 
 // Every three hours
-echo $generator->hours('*/3'); // * */3 * * *
+echo $generator->set(new \Butschster\CronExpression\Parts\Hours\EveryHour()); // * * * * *
+echo $generator->set(new \Butschster\CronExpression\Parts\Hours\EveryHour(3)); // * */3 * * *
 
-echo $generator->hours(25); // Throws an exception: Invalid CRON field value 25 at position 1
+// Between hours
+echo $generator->set(new \Butschster\CronExpression\Parts\Hours\BetweenHours(0, 12)); // * 0-12 * * *
 ```
 
 ### Manipulate days
@@ -153,6 +148,38 @@ echo $generator->twiceDaily(3, 15); // 0 3,15 * * *
 
 // Every day at 03:05, 15:05
 echo $generator->twiceDailyAt(3, 15, 5); // 5 3,15 * * *
+
+// Every month on the last day at 00:00
+echo $generator->lastDayOfMonth(); // 0 0 L * *
+
+// Every month on the last day at 12:00
+echo $generator->lastDayOfMonth(12); // 0 12 L * *
+
+// Every month on the last day at 12:30
+echo $generator->lastDayOfMonth(12, 30); // 30 12 L * *
+
+// Every month on the last weekday at 00:00
+echo $generator->lastWeekdayOfMonth(); // 0 0 LW * *
+
+// Every month on the last weekday at 12:00
+echo $generator->lastWeekdayOfMonth(12); // 0 12 LW * *
+
+// Every month on the last weekday at 12:30
+echo $generator->lastWeekdayOfMonth(12, 30); // 30 12 LW * *
+
+// Every 1, 2, 3 days
+echo $generator->set(new \Butschster\CronExpression\Parts\Days\SpecificDays(1, 2, 3)); // * * 1,2,3 * *
+
+echo $generator->set(new \Butschster\CronExpression\Parts\Days\EveryDay()); // * * * * *
+
+// Every three days
+echo $generator->set(new \Butschster\CronExpression\Parts\Days\EveryDay(3)); // * * */3 * *
+
+// Between days
+echo $generator->set(new \Butschster\CronExpression\Parts\Days\BetweenDays(0, 12)); // * * 0-12 * *
+
+// Last day of month
+echo $generator->set(new \Butschster\CronExpression\Parts\Days\LastDayOfMonth()); // * * L * *
 ```
 
 ### Manipulate days of week
@@ -214,6 +241,31 @@ echo $generator->weeklyOn(Generator::MONDAY, 8); // 0 8 * * 1
 
 // Every monday at 08:06
 echo $generator->weeklyOn(Generator::MONDAY, 8, 6); // 6 8 * * 1
+
+// Every day of a week
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\EveryDaysOfWeek()); // * * * * *
+
+// Every two days of a week
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\EveryDaysOfWeek(2)); // * * * * */2
+
+
+// Every Monday,Wednesday, Friday
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\SpecificDaysOfWeek(Generator::MONDAY, Generator::WEDNESDAY, Generator::FRIDAY)); // * * * * 1,3,5
+
+// Between days of a week
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\BetweenDayOfWeek(Generator::MONDAY, Generator::FRIDAY)); // * * * * 1-5
+
+// Last monday of a week
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\LastDayOwWeek()); // * * * * 1L
+
+// Last friday of a week
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\LastDayOwWeek(Generator::FRIDAY)); // * * * * 5L
+
+// Every first monday of every month
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\NthDayOfWeek()); // * * * * 1#1
+
+// Every third friday of every month
+echo $generator->set(new \Butschster\CronExpression\Parts\DaysOfWeek\NthDayOfWeek(Generator::FRIDAY, 3)); // * * * * 5#3
 ```
 
 ### Manipulate months
@@ -245,19 +297,6 @@ echo $generator->twiceMonthly(15, 24, 10, 30); // 30 10 15,24 * *
 // Every month three times on 12, 24, 30 day at 10:345
 echo $generator->dailyAt(10, 45)->daysOfMonth(12, 24, 30); // 45 10 12,24,30 * *
 
-// Every month on the last day at 00:00
-echo $generator->lastDayOfMonth(); // 0 0 31 * *
-
-// Every month on the last day at 12:00
-echo $generator->lastDayOfMonth(12); // 0 12 31 * *
-
-// Every month on the last day at 12:30
-echo $generator->lastDayOfMonth(12, 30); // 30 12 31 * *
-
-// Every month on the last day at specific date
-$date = new DateTime('2021-02-05');
-echo $generator->lastDayOfMonth(12, 30, $date); // 30 12 28 * *
-
 // Every quarter yyyy-01,03,06,09-01 00:00
 echo $generator->quarterly(); // 0 0 1 1-12/3 *
 
@@ -275,6 +314,21 @@ echo $generator->yearlyOn(Generator::APR, 5, 8); // 0 8 5 4 *
 
 // Every year yyyy-04-05 08:30
 echo $generator->yearlyOn(Generator::APR, 5, 8, 30); // 30 8 5 4 *
+
+// Every month
+echo $generator->set(new \Butschster\CronExpression\Parts\Months\EveryMonth()); // * * * * *
+
+// Every two months
+echo $generator->set(new \Butschster\CronExpression\Parts\Months\EveryMonth(2)); // * * * */2 *
+
+// Specific months: april and december
+echo $generator->set(new \Butschster\CronExpression\Parts\Months\SpecificMonths(Generator::APR, Generator::DEC)); // * * * 4,12 *
+
+// Between april and december
+echo $generator->set(new \Butschster\CronExpression\Parts\Months\BetweenMonths(Generator::APR, Generator::DEC)); // * * * 4-12 *
+
+// Quarterly
+echo $generator->set(new \Butschster\CronExpression\Parts\Months\Quarterly()); // * * * 1-12/3 *
 ```
 
 ### Specific time
@@ -283,11 +337,21 @@ $date = new DateTime('2021-02-05 12:34:26');
 
 // Every year yyyy-02-05 12:34
 echo $generator->on($date); // 34 12 5 2 *
+// or
+echo $generator->set(new \Butschster\CronExpression\Parts\DateTime($date)); // 34 12 5 2 *
 ```
 
 ### Custom expression
+
 ```php
+use Butschster\CronExpression\Parts\Days\SpecificDays;
+use Butschster\CronExpression\Parts\DaysOfWeek\SpecificDaysOfWeek;
+use Butschster\CronExpression\Parts\Hours\EveryHour;
+use Butschster\CronExpression\Parts\Minutes\EveryMinute;
+use Butschster\CronExpression\Parts\Months\SpecificMonths;
+
 // * */2 5,10,15,20,25,30 3,6,9,12 1,3,5,0
+
 echo $generator
     ->yearly()
     ->months(Generator::MAR, Generator::JUN, Generator::SEP, Generator::DEC)
@@ -295,6 +359,17 @@ echo $generator
     ->daysOfWeek(Generator::MONDAY, Generator::WEDNESDAY, Generator::FRIDAY, Generator::SUNDAY)
     ->everyTwoHours()
     ->everyMinute();
+
+// or
+
+echo $generator
+    ->set(
+        new SpecificMonths(Generator::MAR, Generator::JUN, Generator::SEP, Generator::DEC),
+        new SpecificDays(5, 10, 15, 20, 25, 30),
+        new SpecificDaysOfWeek(Generator::MONDAY, Generator::WEDNESDAY, Generator::FRIDAY, Generator::SUNDAY),
+        new EveryHour(2),
+        new EveryMinute()
+    );
 ```
 
 ### Gets next run date
@@ -327,6 +402,66 @@ class Kernel extends ConsoleKernel
 }
 ```
 
+## Create custom expressions
+To create a custom expression class you need implement `Butschster\CronExpression\PartValueInterface`
+
+#### Example 1
+```php
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+class Quarterly implements PartValueInterface
+{
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(CronExpression::MONTH, '1-12/3');
+    }
+}
+```
+
+Using
+```php
+echo \Butschster\CronExpression\Generator::create()->set(new Quarterly()); // * * * 1-12/3 *
+```
+
+#### Example 2
+
+```php
+use Butschster\CronExpression\Parts\Days\SpecificDays;
+use Butschster\CronExpression\Parts\Hours\SpecificHours;
+use Butschster\CronExpression\Parts\Minutes\SpecificMinutes;
+use Butschster\CronExpression\Parts\Months\SpecificMonths;
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+use DateTimeInterface;
+
+class DateTime implements PartValueInterface
+{
+    public function __construct(private DateTimeInterface $time)
+    {
+    }
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $parts = [
+            new SpecificMinutes((int)$this->time->format('i')),
+            new SpecificHours((int)$this->time->format('G')),
+            new SpecificDays((int)$this->time->format('j')),
+            new SpecificMonths((int)$this->time->format('n'))
+        ];
+
+        foreach ($parts as $part) {
+            $part->updateExpression($expression);
+        }
+    }
+}
+```
+
+Using
+```php
+echo \Butschster\CronExpression\Generator::create()->set(new DateTime(new \DateTime('2021-02-05 12:34:26'))); // 34 12 5 2 *
+```
+
 ## Testing
 
 ```bash
diff --git a/src/Expression.php b/src/Expression.php
deleted file mode 100644
index e001062..0000000
--- a/src/Expression.php
+++ /dev/null
@@ -1,56 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Butschster\CronExpression;
-
-use Cron\CronExpression;
-
-class Expression extends CronExpression
-{
-    public function hours(string | int ...$hours): self
-    {
-        $expression = clone $this;
-        $expression->setPart(self::HOUR, implode(',', $hours));
-
-        return $expression;
-    }
-
-    public function minutes(string | int ...$minutes): self
-    {
-        $expression = clone $this;
-        $expression->setPart(self::MINUTE, implode(',', $minutes));
-
-        return $expression;
-    }
-
-    public function daysOfWeek(string | int...$dayOfWeek): self
-    {
-        $dayOfWeek = $dayOfWeek ?: [Generator::MONDAY];
-
-        $expression = clone $this;
-        $expression->setPart(CronExpression::WEEKDAY, implode(',', $dayOfWeek));
-
-        return $expression;
-    }
-
-    public function daysOfMonth(string | int ...$days): self
-    {
-        $days = $days ?: [1];
-
-        $expression = clone $this;
-        $expression->setPart(CronExpression::DAY, implode(',', $days));
-
-        return $expression;
-    }
-
-    public function months(string | int ...$months): self
-    {
-        $months = $months ?: [Generator::JAN];
-
-        $expression = clone $this;
-        $expression->setPart(CronExpression::MONTH, implode(',', $months));
-
-        return $expression;
-    }
-}
diff --git a/src/Generator.php b/src/Generator.php
index d6327f1..f356679 100644
--- a/src/Generator.php
+++ b/src/Generator.php
@@ -4,6 +4,7 @@
 
 namespace Butschster\CronExpression;
 
+use Butschster\CronExpression\Parts\DateTime;
 use Butschster\CronExpression\Traits\Days;
 use Butschster\CronExpression\Traits\Hours;
 use Butschster\CronExpression\Traits\Minutes;
@@ -45,35 +46,42 @@ class Generator
 
     private const DEFAULT = '* * * * *';
 
-    private Expression $expression;
+    private CronExpression $expression;
 
-    public static function create(?Expression $expression = null): self
+    public static function create(?CronExpression $expression = null): self
     {
         return new self($expression);
     }
 
-    public function __construct(?Expression $expression = null)
+    public function __construct(?CronExpression $expression = null)
     {
-        $this->expression = $expression ?? new Expression(self::DEFAULT);
+        $this->expression = $expression ?? new CronExpression(self::DEFAULT);
     }
 
     public function cron(string $expression): self
     {
-        return self::create(new Expression($expression));
+        return self::create(new CronExpression($expression));
+    }
+
+    public function set(PartValueInterface ...$values): self
+    {
+        $expression = clone $this->expression;
+
+        foreach ($values as $value) {
+            $value->updateExpression($expression);
+        }
+
+        return new self($expression);
     }
 
     public function on(DateTimeInterface $time): self
     {
-        return $this
-            ->minutes((int) $time->format('i'))
-            ->hours($time->format('G'))
-            ->daysOfMonth($time->format('j'))
-            ->months($time->format('n'));
+        return $this->set(new DateTime($time));
     }
 
     public function __toString(): string
     {
-        return (string) $this->toExpression();
+        return $this->toExpression();
     }
 
     public function toExpression(): string
@@ -81,7 +89,7 @@ public function toExpression(): string
         return $this->getExpression()->getExpression();
     }
 
-    public function setExpresion(Expression $expression): self
+    public function setExpresion(CronExpression $expression): self
     {
         $this->expression = $expression;
 
diff --git a/src/PartValueInterface.php b/src/PartValueInterface.php
new file mode 100644
index 0000000..d0aff32
--- /dev/null
+++ b/src/PartValueInterface.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression;
+
+use Cron\CronExpression;
+
+interface PartValueInterface
+{
+    public function updateExpression(CronExpression $expression): void;
+}
diff --git a/src/Parts/Between.php b/src/Parts/Between.php
new file mode 100644
index 0000000..273a2b5
--- /dev/null
+++ b/src/Parts/Between.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts;
+
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+use Webmozart\Assert\Assert;
+
+abstract class Between implements PartValueInterface
+{
+    public function __construct(private int $min, private int $max)
+    {
+    }
+
+    abstract public function index(): int;
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(
+            $this->index(),
+            $this->min . '-' . $this->max
+        );
+    }
+}
diff --git a/src/Parts/DateTime.php b/src/Parts/DateTime.php
new file mode 100644
index 0000000..834883a
--- /dev/null
+++ b/src/Parts/DateTime.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts;
+
+use Butschster\CronExpression\Parts\Days\SpecificDays;
+use Butschster\CronExpression\Parts\Hours\SpecificHours;
+use Butschster\CronExpression\Parts\Minutes\SpecificMinutes;
+use Butschster\CronExpression\Parts\Months\SpecificMonths;
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+use DateTimeInterface;
+
+class DateTime implements PartValueInterface
+{
+    public function __construct(private DateTimeInterface $time)
+    {
+    }
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $parts = [
+            new SpecificMinutes((int)$this->time->format('i')),
+            new SpecificHours((int)$this->time->format('G')),
+            new SpecificDays((int)$this->time->format('j')),
+            new SpecificMonths((int)$this->time->format('n'))
+        ];
+
+        foreach ($parts as $part) {
+            $part->updateExpression($expression);
+        }
+    }
+}
diff --git a/src/Parts/Days/BetweenDays.php b/src/Parts/Days/BetweenDays.php
new file mode 100644
index 0000000..0c1cced
--- /dev/null
+++ b/src/Parts/Days/BetweenDays.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Days;
+
+use Butschster\CronExpression\Parts\Between;
+
+class BetweenDays extends Between
+{
+    use DayIndex;
+}
diff --git a/src/Parts/Days/DayIndex.php b/src/Parts/Days/DayIndex.php
new file mode 100644
index 0000000..a74a4ec
--- /dev/null
+++ b/src/Parts/Days/DayIndex.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Days;
+
+use Cron\CronExpression;
+
+trait DayIndex
+{
+    public function index(): int
+    {
+        return CronExpression::DAY;
+    }
+}
diff --git a/src/Parts/Days/EveryDay.php b/src/Parts/Days/EveryDay.php
new file mode 100644
index 0000000..a6656be
--- /dev/null
+++ b/src/Parts/Days/EveryDay.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Days;
+
+use Butschster\CronExpression\Parts\Every;
+
+class EveryDay extends Every
+{
+    use DayIndex;
+}
diff --git a/src/Parts/Days/LastDayOfMonth.php b/src/Parts/Days/LastDayOfMonth.php
new file mode 100644
index 0000000..2dde9d4
--- /dev/null
+++ b/src/Parts/Days/LastDayOfMonth.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Days;
+
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+class LastDayOfMonth implements PartValueInterface
+{
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(CronExpression::DAY, 'L');
+    }
+}
diff --git a/src/Parts/Days/LastWeekday.php b/src/Parts/Days/LastWeekday.php
new file mode 100644
index 0000000..f283ecc
--- /dev/null
+++ b/src/Parts/Days/LastWeekday.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Days;
+
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+class LastWeekday implements PartValueInterface
+{
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(CronExpression::DAY, 'LW');
+    }
+}
diff --git a/src/Parts/Days/SpecificDays.php b/src/Parts/Days/SpecificDays.php
new file mode 100644
index 0000000..2bf9355
--- /dev/null
+++ b/src/Parts/Days/SpecificDays.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Days;
+
+use Butschster\CronExpression\Parts\Specific;
+
+class SpecificDays extends Specific
+{
+    use DayIndex;
+}
diff --git a/src/Parts/DaysOfWeek/BetweenDayOfWeek.php b/src/Parts/DaysOfWeek/BetweenDayOfWeek.php
new file mode 100644
index 0000000..3817562
--- /dev/null
+++ b/src/Parts/DaysOfWeek/BetweenDayOfWeek.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\DaysOfWeek;
+
+use Butschster\CronExpression\Parts\Between;
+
+class BetweenDayOfWeek extends Between
+{
+    use DaysOfWeekIndex;
+}
diff --git a/src/Parts/DaysOfWeek/DaysOfWeekIndex.php b/src/Parts/DaysOfWeek/DaysOfWeekIndex.php
new file mode 100644
index 0000000..1f2a15c
--- /dev/null
+++ b/src/Parts/DaysOfWeek/DaysOfWeekIndex.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\DaysOfWeek;
+
+use Cron\CronExpression;
+
+trait DaysOfWeekIndex
+{
+    public function index(): int
+    {
+        return CronExpression::WEEKDAY;
+    }
+}
diff --git a/src/Parts/DaysOfWeek/EveryDaysOfWeek.php b/src/Parts/DaysOfWeek/EveryDaysOfWeek.php
new file mode 100644
index 0000000..e48694c
--- /dev/null
+++ b/src/Parts/DaysOfWeek/EveryDaysOfWeek.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\DaysOfWeek;
+
+use Butschster\CronExpression\Parts\Every;
+
+class EveryDaysOfWeek extends Every
+{
+    use DaysOfWeekIndex;
+}
diff --git a/src/Parts/DaysOfWeek/LastDayOwWeek.php b/src/Parts/DaysOfWeek/LastDayOwWeek.php
new file mode 100644
index 0000000..2b8cbc2
--- /dev/null
+++ b/src/Parts/DaysOfWeek/LastDayOwWeek.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\DaysOfWeek;
+
+use Butschster\CronExpression\Generator;
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+class LastDayOwWeek implements PartValueInterface
+{
+    public function __construct(private int $dayOfWeek = Generator::MONDAY)
+    {
+    }
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(CronExpression::WEEKDAY, $this->dayOfWeek . 'L');
+    }
+}
diff --git a/src/Parts/DaysOfWeek/NthDayOfWeek.php b/src/Parts/DaysOfWeek/NthDayOfWeek.php
new file mode 100644
index 0000000..14259e4
--- /dev/null
+++ b/src/Parts/DaysOfWeek/NthDayOfWeek.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\DaysOfWeek;
+
+use Butschster\CronExpression\Generator;
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+class NthDayOfWeek implements PartValueInterface
+{
+    public function __construct(private int $dayOfWeek = Generator::MONDAY, private int $nth = 1)
+    {
+    }
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(CronExpression::WEEKDAY, $this->dayOfWeek . '#' . $this->nth);
+    }
+}
diff --git a/src/Parts/DaysOfWeek/SpecificDaysOfWeek.php b/src/Parts/DaysOfWeek/SpecificDaysOfWeek.php
new file mode 100644
index 0000000..f2cb866
--- /dev/null
+++ b/src/Parts/DaysOfWeek/SpecificDaysOfWeek.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\DaysOfWeek;
+
+use Butschster\CronExpression\Parts\Specific;
+
+class SpecificDaysOfWeek extends Specific
+{
+    use DaysOfWeekIndex;
+}
diff --git a/src/Parts/Every.php b/src/Parts/Every.php
new file mode 100644
index 0000000..00a17b0
--- /dev/null
+++ b/src/Parts/Every.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts;
+
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+abstract class Every implements PartValueInterface
+{
+    public function __construct(private ?int $interval = null)
+    {
+    }
+
+    abstract public function index(): int;
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(
+            $this->index(),
+            $this->interval ? '*/' . $this->interval : '*'
+        );
+    }
+}
diff --git a/src/Parts/Hours/BetweenHours.php b/src/Parts/Hours/BetweenHours.php
new file mode 100644
index 0000000..f2896c0
--- /dev/null
+++ b/src/Parts/Hours/BetweenHours.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Hours;
+
+use Butschster\CronExpression\Parts\Between;
+
+class BetweenHours extends Between
+{
+    use HourIndex;
+}
diff --git a/src/Parts/Hours/EveryHour.php b/src/Parts/Hours/EveryHour.php
new file mode 100644
index 0000000..4afe96b
--- /dev/null
+++ b/src/Parts/Hours/EveryHour.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Hours;
+
+use Butschster\CronExpression\Parts\Every;
+
+class EveryHour extends Every
+{
+    use HourIndex;
+}
diff --git a/src/Parts/Hours/HourIndex.php b/src/Parts/Hours/HourIndex.php
new file mode 100644
index 0000000..42f83b3
--- /dev/null
+++ b/src/Parts/Hours/HourIndex.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Hours;
+
+use Cron\CronExpression;
+
+trait HourIndex
+{
+    public function index(): int
+    {
+        return CronExpression::HOUR;
+    }
+}
diff --git a/src/Parts/Hours/SpecificHours.php b/src/Parts/Hours/SpecificHours.php
new file mode 100644
index 0000000..266ff38
--- /dev/null
+++ b/src/Parts/Hours/SpecificHours.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Hours;
+
+use Butschster\CronExpression\Parts\Specific;
+
+class SpecificHours extends Specific
+{
+    use HourIndex;
+}
diff --git a/src/Parts/Minutes/BetweenMinutes.php b/src/Parts/Minutes/BetweenMinutes.php
new file mode 100644
index 0000000..34a2437
--- /dev/null
+++ b/src/Parts/Minutes/BetweenMinutes.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Minutes;
+
+use Butschster\CronExpression\Parts\Between;
+
+class BetweenMinutes extends Between
+{
+    use MinuteIndex;
+}
diff --git a/src/Parts/Minutes/EveryMinute.php b/src/Parts/Minutes/EveryMinute.php
new file mode 100644
index 0000000..a1eedda
--- /dev/null
+++ b/src/Parts/Minutes/EveryMinute.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Minutes;
+
+use Butschster\CronExpression\Parts\Every;
+
+class EveryMinute extends Every
+{
+    use MinuteIndex;
+}
diff --git a/src/Parts/Minutes/MinuteIndex.php b/src/Parts/Minutes/MinuteIndex.php
new file mode 100644
index 0000000..bb5772f
--- /dev/null
+++ b/src/Parts/Minutes/MinuteIndex.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Minutes;
+
+use Cron\CronExpression;
+
+trait MinuteIndex
+{
+    public function index(): int
+    {
+        return CronExpression::MINUTE;
+    }
+}
diff --git a/src/Parts/Minutes/SpecificMinutes.php b/src/Parts/Minutes/SpecificMinutes.php
new file mode 100644
index 0000000..c5e291e
--- /dev/null
+++ b/src/Parts/Minutes/SpecificMinutes.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Minutes;
+
+use Butschster\CronExpression\Parts\Specific;
+
+class SpecificMinutes extends Specific
+{
+    use MinuteIndex;
+}
diff --git a/src/Parts/Months/BetweenMonths.php b/src/Parts/Months/BetweenMonths.php
new file mode 100644
index 0000000..55a908d
--- /dev/null
+++ b/src/Parts/Months/BetweenMonths.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Months;
+
+use Butschster\CronExpression\Parts\Between;
+
+class BetweenMonths extends Between
+{
+    use MonthIndex;
+}
diff --git a/src/Parts/Months/EveryMonth.php b/src/Parts/Months/EveryMonth.php
new file mode 100644
index 0000000..0a867bb
--- /dev/null
+++ b/src/Parts/Months/EveryMonth.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Months;
+
+use Butschster\CronExpression\Parts\Every;
+
+class EveryMonth extends Every
+{
+    use MonthIndex;
+}
diff --git a/src/Parts/Months/MonthIndex.php b/src/Parts/Months/MonthIndex.php
new file mode 100644
index 0000000..636e35c
--- /dev/null
+++ b/src/Parts/Months/MonthIndex.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Months;
+
+use Cron\CronExpression;
+
+trait MonthIndex
+{
+    public function index(): int
+    {
+        return CronExpression::MONTH;
+    }
+}
diff --git a/src/Parts/Months/Quarterly.php b/src/Parts/Months/Quarterly.php
new file mode 100644
index 0000000..e42b1bc
--- /dev/null
+++ b/src/Parts/Months/Quarterly.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Months;
+
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+class Quarterly implements PartValueInterface
+{
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(CronExpression::MONTH, '1-12/3');
+    }
+}
diff --git a/src/Parts/Months/SpecificMonths.php b/src/Parts/Months/SpecificMonths.php
new file mode 100644
index 0000000..c8e542e
--- /dev/null
+++ b/src/Parts/Months/SpecificMonths.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts\Months;
+
+use Butschster\CronExpression\Parts\Specific;
+
+class SpecificMonths extends Specific
+{
+    use MonthIndex;
+}
diff --git a/src/Parts/Specific.php b/src/Parts/Specific.php
new file mode 100644
index 0000000..358e336
--- /dev/null
+++ b/src/Parts/Specific.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Butschster\CronExpression\Parts;
+
+use Butschster\CronExpression\PartValueInterface;
+use Cron\CronExpression;
+
+abstract class Specific implements PartValueInterface
+{
+    /** @var array<int> */
+    private array $values;
+
+    public function __construct(int ...$values)
+    {
+        $this->values = $values;
+    }
+
+    abstract public function index(): int;
+
+    public function updateExpression(CronExpression $expression): void
+    {
+        $expression->setPart(
+            $this->index(),
+            implode(',', $this->values)
+        );
+    }
+}
diff --git a/src/Traits/Days.php b/src/Traits/Days.php
index 87767e7..78b9a65 100644
--- a/src/Traits/Days.php
+++ b/src/Traits/Days.php
@@ -4,20 +4,26 @@
 
 namespace Butschster\CronExpression\Traits;
 
+use Butschster\CronExpression\Parts\Days\LastDayOfMonth;
+use Butschster\CronExpression\Parts\Days\LastWeekday;
+use Butschster\CronExpression\Parts\Hours\SpecificHours;
+use Butschster\CronExpression\Parts\Minutes\SpecificMinutes;
+
 trait Days
 {
     public function daily(int ...$hours): self
     {
-        $hours = $hours ? implode(',', $hours) : 0;
+        $hours = $hours ?: [0];
 
-        return $this->minutes(0)
-            ->hours($hours);
+        return $this->hourly()->set(new SpecificHours(...$hours));
     }
 
     public function dailyAt(int $hour, int $minute = 0): self
     {
-        return $this->minutes($minute)
-            ->hours($hour);
+        return $this->set(
+            new SpecificMinutes($minute),
+            new SpecificHours($hour)
+        );
     }
 
     public function twiceDaily($first = 1, $second = 13): self
@@ -27,7 +33,17 @@ public function twiceDaily($first = 1, $second = 13): self
 
     public function twiceDailyAt($first = 1, $second = 13, $minute = 0): self
     {
-        return $this->daily($first, $second)
-            ->minutes($minute);
+        return $this->daily($first, $second)->set(new SpecificMinutes($minute));
+    }
+
+    public function lastDayOfMonth(int $hour = 0, int $minute = 0): self
+    {
+        return $this->dailyAt($hour, $minute)->set(new LastDayOfMonth());
+    }
+
+    public function lastWeekdayOfMonth(int $hour = 0, int $minute = 0): self
+    {
+        return $this->dailyAt($hour, $minute)
+            ->set(new LastWeekday());
     }
 }
diff --git a/src/Traits/Hours.php b/src/Traits/Hours.php
index 3317112..da18567 100644
--- a/src/Traits/Hours.php
+++ b/src/Traits/Hours.php
@@ -4,46 +4,43 @@
 
 namespace Butschster\CronExpression\Traits;
 
+use Butschster\CronExpression\Parts\Hours\EveryHour;
+use Butschster\CronExpression\Parts\Minutes\SpecificMinutes;
+
 trait Hours
 {
     public function hourly(): self
     {
-        return $this->minutes(0);
+        return $this->set(new SpecificMinutes(0));
     }
 
     public function hourlyAt(int ...$minute): self
     {
-        return $this->minutes(...$minute);
+        return $this->set(new SpecificMinutes(...$minute));
+    }
+
+    public function everyHours(?int $hour = null): self
+    {
+        return $this->hourly()->set(new EveryHour($hour));
     }
 
     public function everyTwoHours(): self
     {
-        return $this->minutes(0)
-            ->hours('*/2');
+        return $this->everyHours(2);
     }
 
     public function everyThreeHours(): self
     {
-        return $this->minutes(0)
-            ->hours('*/3');
+        return $this->everyHours(3);
     }
 
     public function everyFourHours(): self
     {
-        return $this->minutes(0)
-            ->hours('*/4');
+        return $this->everyHours(4);
     }
 
     public function everySixHours(): self
     {
-        return $this->minutes(0)
-            ->hours('*/6');
-    }
-
-    public function hours(string | int ...$hours): self
-    {
-        return self::create(
-            $this->expression->hours(...$hours)
-        );
+        return $this->everyHours(6);
     }
 }
diff --git a/src/Traits/Minutes.php b/src/Traits/Minutes.php
index 4708eab..f514592 100644
--- a/src/Traits/Minutes.php
+++ b/src/Traits/Minutes.php
@@ -4,11 +4,14 @@
 
 namespace Butschster\CronExpression\Traits;
 
+use Butschster\CronExpression\Parts\Minutes\EveryMinute;
+use Butschster\CronExpression\Parts\Minutes\SpecificMinutes;
+
 trait Minutes
 {
-    public function everyMinute(): self
+    public function everyMinute(?int $minute = null): self
     {
-        return $this->minutes('*');
+        return $this->set(new EveryMinute($minute));
     }
 
     public function everyEvenMinute(): self
@@ -18,43 +21,36 @@ public function everyEvenMinute(): self
 
     public function everyTwoMinutes(): self
     {
-        return $this->minutes('*/2');
+        return $this->everyMinute(2);
     }
 
     public function everyThreeMinutes(): self
     {
-        return $this->minutes('*/3');
+        return $this->everyMinute(3);
     }
 
     public function everyFourMinutes(): self
     {
-        return $this->minutes('*/4');
+        return $this->everyMinute(4);
     }
 
     public function everyFiveMinutes(): self
     {
-        return $this->minutes('*/5');
+        return $this->everyMinute(5);
     }
 
     public function everyTenMinutes(): self
     {
-        return $this->minutes('*/10');
+        return $this->everyMinute(10);
     }
 
     public function everyFifteenMinutes(): self
     {
-        return $this->minutes('*/15');
+        return $this->everyMinute(15);
     }
 
     public function everyThirtyMinutes(): self
     {
-        return $this->minutes(0, 30);
-    }
-
-    public function minutes(string | int ...$minutes): self
-    {
-        return self::create(
-            $this->expression->minutes(...$minutes)
-        );
+        return $this->set(new SpecificMinutes(0, 30));
     }
 }
diff --git a/src/Traits/Months.php b/src/Traits/Months.php
index 6fc5f98..4cfa5ae 100644
--- a/src/Traits/Months.php
+++ b/src/Traits/Months.php
@@ -4,16 +4,15 @@
 
 namespace Butschster\CronExpression\Traits;
 
-use DateTime;
-use DateTimeInterface;
+use Butschster\CronExpression\Parts\Days\SpecificDays;
+use Butschster\CronExpression\Parts\DaysOfWeek\LastDayOwWeek;
+use Butschster\CronExpression\Parts\DaysOfWeek\NthDayOfWeek;
 
 trait Months
 {
-    public function daysOfMonth(string | int ...$days): self
+    public function daysOfMonth(int ...$days): self
     {
-        return self::create(
-            $this->expression->daysOfMonth(...$days)
-        );
+        return $this->set(new SpecificDays(...$days));
     }
 
     public function monthly(int $hour = 0, int $minute = 0): self
@@ -35,11 +34,13 @@ public function twiceMonthly(int $first = 1, int $second = 16, int $hour = 0, in
             ->daysOfMonth($first, $second);
     }
 
-    public function lastDayOfMonth(int $hour = 0, int $minute = 0, ?DateTimeInterface $time = null): self
+    public function lastDayOfWeekEveryMonth(int $dayOfWeek = self::MONDAY, int $hour = 0, int $minute = 0): self
     {
-        $time = $time ?? new DateTime();
+        return $this->dailyAt($hour, $minute)->set(new LastDayOwWeek($dayOfWeek));
+    }
 
-        return $this->dailyAt($hour, $minute)
-            ->daysOfMonth((int)$time->format('t'));
+    public function nthDayOfWeekEveryMonth(int $dayOfWeek = self::MONDAY, int $nth = 1, int $hour = 0, int $minute = 0): self
+    {
+        return $this->dailyAt($hour, $minute)->set(new NthDayOfWeek($dayOfWeek, $nth));
     }
 }
diff --git a/src/Traits/Weeks.php b/src/Traits/Weeks.php
index 16bd5b8..753efa3 100644
--- a/src/Traits/Weeks.php
+++ b/src/Traits/Weeks.php
@@ -4,31 +4,31 @@
 
 namespace Butschster\CronExpression\Traits;
 
+use Butschster\CronExpression\Parts\DaysOfWeek\BetweenDayOfWeek;
+use Butschster\CronExpression\Parts\DaysOfWeek\SpecificDaysOfWeek;
+
 trait Weeks
 {
-    public function daysOfWeek(string | int...$dayOfWeek): self
+    public function daysOfWeek(int...$dayOfWeek): self
     {
-        return self::create(
-            $this->expression->daysOfWeek(...$dayOfWeek)
-        );
+        return $this->set(new SpecificDaysOfWeek(...$dayOfWeek));
     }
 
     public function weekly(int ...$dayOfWeek): self
     {
         $dayOfWeek = $dayOfWeek ?: [0];
 
-        return $this->daily()
-            ->daysOfWeek(...$dayOfWeek);
+        return $this->daily()->daysOfWeek(...$dayOfWeek);
     }
 
     public function weekdays(): self
     {
-        return $this->daysOfWeek(self::MONDAY . '-' . self::FRIDAY);
+        return $this->set(new BetweenDayOfWeek(self::MONDAY, self::FRIDAY));
     }
 
     public function weekends(): self
     {
-        return $this->daysOfWeek(self::SATURDAY . ',' . self::SUNDAY);
+        return $this->daysOfWeek(self::SATURDAY, self::SUNDAY);
     }
 
     public function mondays(): self
diff --git a/src/Traits/Years.php b/src/Traits/Years.php
index ec95e90..2fddff9 100644
--- a/src/Traits/Years.php
+++ b/src/Traits/Years.php
@@ -4,25 +4,26 @@
 
 namespace Butschster\CronExpression\Traits;
 
+use Butschster\CronExpression\Parts\Months\Quarterly;
+use Butschster\CronExpression\Parts\Months\SpecificMonths;
+
 trait Years
 {
-    public function months(string | int ...$months): self
+    public function months(int ...$months): self
     {
-        return self::create(
-            $this->expression->months(...$months)
-        );
+        $months = $months ?: [self::JAN];
+
+        return $this->set(new SpecificMonths(...$months));
     }
 
     public function quarterly(): self
     {
-        return $this->monthly()
-            ->months('1-12/3');
+        return $this->monthly()->set(new Quarterly());
     }
 
     public function yearly(int ...$months): self
     {
-        return $this->monthly()
-            ->months(...$months);
+        return $this->monthly()->months(...$months);
     }
 
     public function yearlyOn(int $month = self::JAN, int $dayOfMonth = 1, int $hour = 0, int $minute = 0): self
diff --git a/tests/GeneratorTest.php b/tests/GeneratorTest.php
index 17fbdf2..950470b 100644
--- a/tests/GeneratorTest.php
+++ b/tests/GeneratorTest.php
@@ -5,6 +5,15 @@
 namespace Butschster\CronExpression\Tests;
 
 use Butschster\CronExpression\Generator;
+use Butschster\CronExpression\Parts\Days\SpecificDays;
+use Butschster\CronExpression\Parts\DaysOfWeek\SpecificDaysOfWeek;
+use Butschster\CronExpression\Parts\Hours\BetweenHours;
+use Butschster\CronExpression\Parts\Hours\EveryHour;
+use Butschster\CronExpression\Parts\Hours\SpecificHours;
+use Butschster\CronExpression\Parts\Minutes\BetweenMinutes;
+use Butschster\CronExpression\Parts\Minutes\EveryMinute;
+use Butschster\CronExpression\Parts\Minutes\SpecificMinutes;
+use Butschster\CronExpression\Parts\Months\SpecificMonths;
 use DateTime;
 use InvalidArgumentException;
 
@@ -39,9 +48,9 @@ public function testEveryXMinutes()
 
     public function testSetsMinutes()
     {
-        $this->assertExpression('15,30,45 * * * *', $this->generator->minutes(15, 30, 45));
-        $this->assertExpression('*/3 * * * *', $this->generator->minutes('*/3'));
-        $this->assertExpression('10-30 * * * *', $this->generator->minutes('10-30'));
+        $this->assertExpression('15,30,45 * * * *', $this->generator->set(new SpecificMinutes(15, 30, 45)));
+        $this->assertExpression('*/3 * * * *', $this->generator->set(new EveryMinute(3)));
+        $this->assertExpression('10-30 * * * *', $this->generator->set(new BetweenMinutes(10, 30)));
     }
 
     public function testInvalidMinutesShouldThrowAnException()
@@ -49,7 +58,7 @@ public function testInvalidMinutesShouldThrowAnException()
         $this->expectException(InvalidArgumentException::class);
         $this->expectErrorMessage('Invalid CRON field value 61 at position 0');
 
-        $this->generator->minutes(61);
+        $this->generator->set(new SpecificMinutes(61));
     }
 
     public function testHourly()
@@ -74,10 +83,11 @@ public function testEveryXHours()
 
     public function testSetsHours()
     {
-        $this->assertExpression('* 1,2,3 * * *', $this->generator->hours(1, 2, 3));
-        $this->assertExpression('* */3 * * *', $this->generator->hours('*/3'));
+        $this->assertExpression('* 1,2,3 * * *', $this->generator->set(new SpecificHours(1, 2, 3)));
+        $this->assertExpression('* */3 * * *', $this->generator->set(new EveryHour(3)));
+        $this->assertExpression('* 3-6 * * *', $this->generator->set(new BetweenHours(3, 6)));
 
-        $this->assertExpression('15 1,2,3 * * *', $this->generator->hourlyAt(15)->hours(1, 2, 3));
+        $this->assertExpression('15 1,2,3 * * *', $this->generator->hourlyAt(15)->set(new SpecificHours(1, 2, 3)));
     }
 
     public function testInvalidHoursShouldThrowAnException()
@@ -85,7 +95,7 @@ public function testInvalidHoursShouldThrowAnException()
         $this->expectException(InvalidArgumentException::class);
         $this->expectErrorMessage('Invalid CRON field value 25 at position 1');
 
-        $this->generator->hours(25);
+        $this->generator->set(new SpecificHours(25));
     }
 
     public function testDaily()
@@ -190,12 +200,31 @@ public function testMonthlyOn()
 
     public function testLastDayOfMonth()
     {
-        $currentDate = new DateTime();
-        $this->assertExpression('0 0 ' . $currentDate->format('t') . ' * *', $this->generator->lastDayOfMonth());
-        $this->assertExpression('31 12 ' . $currentDate->format('t') . ' * *', $this->generator->lastDayOfMonth(12, 31));
+        $this->assertExpression('0 0 L * *', $this->generator->lastDayOfMonth());
+        $this->assertExpression('31 12 L * *', $this->generator->lastDayOfMonth(12, 31));
+    }
+
+    public function testLastWeekdayOfMonth()
+    {
+        $this->assertExpression('0 0 LW * *', $this->generator->lastWeekdayOfMonth());
+        $this->assertExpression('31 12 LW * *', $this->generator->lastWeekdayOfMonth(12, 31));
+    }
 
-        $date = new DateTime('2021-02-05');
-        $this->assertExpression('31 12 28 * *', $this->generator->lastDayOfMonth(12, 31, $date));
+    public function testLastDayOfWeekEveryMonth()
+    {
+        $this->assertExpression('0 0 * * 1L', $this->generator->lastDayOfWeekEveryMonth());
+        $this->assertExpression('0 0 * * 5L', $this->generator->lastDayOfWeekEveryMonth(Generator::FRIDAY));
+        $this->assertExpression('0 12 * * 5L', $this->generator->lastDayOfWeekEveryMonth(Generator::FRIDAY, 12));
+        $this->assertExpression('30 12 * * 5L', $this->generator->lastDayOfWeekEveryMonth(Generator::FRIDAY, 12, 30));
+    }
+
+    public function testNthDayOfWeekEveryMonth()
+    {
+        $this->assertExpression('0 0 * * 1#1', $this->generator->nthDayOfWeekEveryMonth());
+        $this->assertExpression('0 0 * * 5#1', $this->generator->nthDayOfWeekEveryMonth(Generator::FRIDAY));
+        $this->assertExpression('0 0 * * 5#3', $this->generator->nthDayOfWeekEveryMonth(Generator::FRIDAY, 3));
+        $this->assertExpression('0 12 * * 5#3', $this->generator->nthDayOfWeekEveryMonth(Generator::FRIDAY, 3, 12));
+        $this->assertExpression('39 12 * * 5#3', $this->generator->nthDayOfWeekEveryMonth(Generator::FRIDAY, 3, 12, 39));
     }
 
     public function testQuarterly()
@@ -241,4 +270,19 @@ public function testMixedExpression()
                 ->everyMinute()
         );
     }
+
+    public function testMixedExpressionFromParts()
+    {
+        $this->assertExpression(
+            '* */2 5,10,15,20,25,30 3,6,9,12 1,3,5,0',
+            $this->generator
+                ->set(
+                    new SpecificMonths(Generator::MAR, Generator::JUN, Generator::SEP, Generator::DEC),
+                    new SpecificDays(5, 10, 15, 20, 25, 30),
+                    new SpecificDaysOfWeek(Generator::MONDAY, Generator::WEDNESDAY, Generator::FRIDAY, Generator::SUNDAY),
+                    new EveryHour(2),
+                    new EveryMinute()
+                )
+        );
+    }
 }