The Kupo EZ Grip Finger with Baby 5/8" Stud and Receiver has a 5/8" stud on one side and a 5/8" receiver on the other connected by a large ball joint. The baby receiver has a metal knob to lock it securely in place. With the knob removed, the outside of the receiver is a Junior 1 1/8" pin that can fit into any junior receiver. The ball joint is locked in place with a large metal knob with needle bearings to give you maximum torque.