diff --git a/src/traits/ExtendableZodSchemaObject.ts b/src/traits/ExtendableZodSchemaObject.ts
index f22d191..8e5347a 100644
--- a/src/traits/ExtendableZodSchemaObject.ts
+++ b/src/traits/ExtendableZodSchemaObject.ts
@@ -37,7 +37,7 @@ export const ExtendableZodSchemaObject = trait(
             },
         ): (
             AbstractClass<
-                Extend<[InstanceType<Super>, Values]>,
+                Extend<[SuperInstance, Values]>,
                 [values: Values]
             > &
             Extend<[