Opens With Your Vehicle Ignition Key -- Stainless Steel 5/8" Diameter Shaft --Fits Class 3, 4 and 5 Hitches (2-2.5"" square receiver) -- Weather Proof -- Auto Return Spring Locks Automatically When Key is Removed --Double Ball Bearing Locking Mechanism -- Plate Tumbler Sidebar to Prevent Picking and Bumping -- Stainless Steel Lock Shutter to Keep Out Dirt and Moisture -- Limited Lifetime Warranty