Keep your trailer on your vehicle with this coupler lock that opens with your vehicle ignition key. Fits couplers from 1/2" to 3 3/8" and any size in between. Stainless Steel Pin Lock slides back and forth along pin for ease of use. 1/8" incremental adjustments allows for a snug fit. Plate tumbler sidebar to prevent picking and bumping. Stainless steel lock shutter to keep out dirt and moisture. Limited Lifetime Warranty.