Featuring patented BOLT Breakthrough One-Key Lock Technology the BOLT Coupler Pin Lock works with your vehicle ignition key. Fully adjustable from 1/2 to 3 3/8 the BOLT Coupler Pin Lock slides back and forth with ease to fit virtually any coupler. The stainless steel pin gives you the security you have come to expect with BOLT Locks while the lock shutter keeps out dirt and moisture.