diff --git a/libtempered/temper_type.c b/libtempered/temper_type.c
index 1b00b20..5cef273 100644
--- a/libtempered/temper_type.c
+++ b/libtempered/temper_type.c
@@ -10,6 +10,7 @@
 #include "type_hid/sht1x.h"
 #include "type_hid/ntc.h"
 #include "type_hid/si7005.h"
+#include "type_hid/si7021.h"
 
 // This is an array of known TEMPer types.
 struct temper_type known_temper_types[]={
@@ -37,6 +38,8 @@ struct temper_type known_temper_types[]={
 			.subtype_strings = (char *[]){
 				"TEMPerHumV1.0rHu",
 				"TEMPerHumM12V1.0",
+				"TEMPerHumM12V1.2",
+				"TEMPerHumM12V1.3",
 				NULL
 			}
 		},
@@ -103,6 +106,68 @@ struct temper_type known_temper_types[]={
 					}
 				}
 			},
+			(struct temper_subtype*)&(struct temper_subtype_hid){
+				.base = {
+					.id = 2,
+					.name = "TEMPerHumM12V1.2",
+					.open = tempered_type_hid_subtype_open,
+					.read_sensors = tempered_type_hid_read_sensors,
+					.get_temperature = tempered_type_hid_get_temperature,
+					.get_humidity = tempered_type_hid_get_humidity
+				},
+				.sensor_group_count = 1,
+				.sensor_groups = (struct tempered_type_hid_sensor_group[]){
+					{
+						.query = {
+							.length = 9,
+							.data = (unsigned char[]){ 0, 1, 0x80, 0x33, 1, 0, 0, 0, 0 }
+						},
+						.read_sensors = tempered_type_hid_read_sensor_group,
+						.sensor_count = 1,
+						.sensors = (struct tempered_type_hid_sensor[]){
+							{
+								.get_temperature = tempered_type_hid_get_temperature_si7021,
+								.get_humidity = tempered_type_hid_get_humidity_si7021,
+								.temperature_high_byte_offset = 2,
+								.temperature_low_byte_offset = 3,
+								.humidity_high_byte_offset = 4,
+								.humidity_low_byte_offset = 5
+							}
+						}
+					}
+				}
+			},
+			(struct temper_subtype*)&(struct temper_subtype_hid){
+				.base = {
+					.id = 3,
+					.name = "TEMPerHumM12V1.3",
+					.open = tempered_type_hid_subtype_open,
+					.read_sensors = tempered_type_hid_read_sensors,
+					.get_temperature = tempered_type_hid_get_temperature,
+					.get_humidity = tempered_type_hid_get_humidity
+				},
+				.sensor_group_count = 1,
+				.sensor_groups = (struct tempered_type_hid_sensor_group[]){
+					{
+						.query = {
+							.length = 9,
+							.data = (unsigned char[]){ 0, 1, 0x80, 0x33, 1, 0, 0, 0, 0 }
+						},
+						.read_sensors = tempered_type_hid_read_sensor_group,
+						.sensor_count = 1,
+						.sensors = (struct tempered_type_hid_sensor[]){
+							{
+								.get_temperature = tempered_type_hid_get_temperature_si7021,
+								.get_humidity = tempered_type_hid_get_humidity_si7021,
+								.temperature_high_byte_offset = 2,
+								.temperature_low_byte_offset = 3,
+								.humidity_high_byte_offset = 4,
+								.humidity_low_byte_offset = 5
+							}
+						}
+					}
+				}
+			},
 			NULL // List terminator for subtypes
 		}
 	},
diff --git a/libtempered/type_hid/si7021.c b/libtempered/type_hid/si7021.c
new file mode 100644
index 0000000..0bf1506
--- /dev/null
+++ b/libtempered/type_hid/si7021.c
@@ -0,0 +1,69 @@
+#include <stdbool.h>
+#include <string.h>
+
+#include "type-info.h"
+#include "../tempered-internal.h"
+
+bool tempered_type_hid_get_temperature_si7021(
+	tempered_device *device, struct tempered_type_hid_sensor *sensor,
+	struct tempered_type_hid_query_result *group_data, float *tempC
+) {
+	if (
+		group_data->length <= sensor->temperature_high_byte_offset ||
+		group_data->length <= sensor->temperature_low_byte_offset
+	) {
+		tempered_set_error(
+			device, strdup( "Not enough data was read from the sensor." )
+		);
+		return false;
+	}
+	
+	// Convert from two separate data bytes to a single integer.
+	// The result should be an unsigned int between 0x0000 and 0xFFFF.
+	int low_byte_offset = sensor->temperature_low_byte_offset;
+	int high_byte_offset = sensor->temperature_high_byte_offset;
+	int temp = ( group_data->data[low_byte_offset] & 0xFF )
+		+ ( ( group_data->data[high_byte_offset] & 0xFF ) << 8 )
+	;
+	
+	// These formulas and values are based on the Silicon Labs Si7021 datasheet
+	*tempC = 175.72*temp/65536 - 46.85;
+	
+	return true;
+}
+
+bool tempered_type_hid_get_humidity_si7021(
+	tempered_device *device, struct tempered_type_hid_sensor *sensor,
+	struct tempered_type_hid_query_result *group_data, float *rel_hum
+) {
+	float tempC;
+	if (
+		!tempered_type_hid_get_temperature_si7021(
+			device, sensor, group_data, &tempC
+		)
+	) {
+		return false;
+	}
+	
+	if (
+		group_data->length <= sensor->humidity_high_byte_offset ||
+		group_data->length <= sensor->humidity_low_byte_offset
+	)
+	{
+		tempered_set_error(
+			device, strdup( "Not enough data was read from the sensor." )
+		);
+		return false;
+	}
+	
+	int low_byte_offset = sensor->humidity_low_byte_offset;
+	int high_byte_offset = sensor->humidity_high_byte_offset;
+	int rh = ( group_data->data[low_byte_offset] & 0xFF )
+		+ ( ( group_data->data[high_byte_offset] & 0xFF ) << 8 )
+	;
+	
+	// These formulas and values are based on the Silicon Labs Si7021 datasheet
+	*rel_hum = 125.*rh/65536 - 6;
+	
+	return true;
+}
diff --git a/libtempered/type_hid/si7021.h b/libtempered/type_hid/si7021.h
new file mode 100644
index 0000000..7b5de85
--- /dev/null
+++ b/libtempered/type_hid/si7021.h
@@ -0,0 +1,20 @@
+#ifndef TEMPERED__TYPE_HID__SI7021_H
+#define TEMPERED__TYPE_HID__SI7021_H
+
+#include <stdbool.h>
+
+#include "type-info.h"
+
+// These methods are for the Silicon Labs Si7021 chip.
+
+bool tempered_type_hid_get_temperature_si7021(
+	tempered_device *device, struct tempered_type_hid_sensor *sensor,
+	struct tempered_type_hid_query_result *group_data, float *tempC
+);
+
+bool tempered_type_hid_get_humidity_si7021(
+	tempered_device *device, struct tempered_type_hid_sensor *sensor,
+	struct tempered_type_hid_query_result *group_data, float *rel_hum
+);
+
+#endif