Trimax TH43 Chrome Keyed-Alike Lock Set, Includes T3, Th4 The 5/8 inch pin fits all Class III, IV and V receiver hitches The extended pin fits the Rapid Hitch System by Andersen Exclusive internal O-ring and cap help seal out dirt and corrosion for trouble free use High quality tubular key won't bend or break Rugged lock can't "pop" open or be false locked