Heininger 6032 HitchMate Trailer Coupler Lock Fits all 2 inch and 2-5/16 inch lip-engaging, trigger style couplers Fits both flat and rolled lip couplers Removable adaptor, adaptor used for snug, non-rattle fit on flat lip couplers Coupler should have a flat or rolled lip around the bottom; maximum lip width: 4-1/2 inches Made in USA