Pac Radio Replacement Interface with Onstar Retention for Select GM Class Ii Vehicles - OS-2X These original Pac Radio Replacement Interface with Onstar Retention for Select GM Class Ii Vehicles - OS-2X are found in the category of Automotive. It has a Product # of OS-2X. The product is known as Pac Radio Replacement Interface with Onstar Retention for Select GM Class Ii Vehicles - OS-2X.