diff --git a/lib/set_as_primary.rb b/lib/set_as_primary.rb
index 3d5b863..395770f 100644
--- a/lib/set_as_primary.rb
+++ b/lib/set_as_primary.rb
@@ -87,7 +87,7 @@ def _polymorphic_condition_options
 
       {
         "#{_klass._owner_key}_id".to_sym =>  owner.id,
-        "#{_klass._owner_key}_type".to_sym => owner.class.name
+        "#{_klass._owner_key}_type".to_sym => owner.class.polymorphic_name
       }
     end