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 adjustment allows for a snug fit -- Weather Proof -- Plate Tumbler Sidebar to Prevent Picking and Bumping -- Stainless Steel Lock Shutter to Keep Out Dirt and Moisture -- Limited Lifetime Warranty