OTC 29501A Replacement Flat-Top Forcing Screw Insert For OTC CA6636 Connected Adapter C-frames. Patented connection and adapter design uses spring-loaded stainless steel ball bearings to securely attach connected cups and adapters to the C-frame and forcing screw. Works with most OTC ball joint kits, cups, and adapters. No O-rings or removable fasteners to lose, damage, or replace. Rugged, high quality materials ensure high strength and a long service life.