Master Locks "Keyed Alike" hitch receiver and coupler lock set use the same key in for both locks. This means less hassle and one fewer key to worry about while protecting your trailer from would-be thieves. The 1/2" hitch receiver lock fits all Class 3 trailer hitches. The coupler lock is adjustable to size different positions to fit most couplers. Made of stainless steel for maximum corrosion protection.