This 5/8” diameter hitch lock is for 2” x 2” Class III & IV receiver hitches requiring a 5/8” diameter pin. Use in place of standard pin and clip. Prevents drawbar or accessory (bike rack/cargo carrier) theft. Lock is double nickel chrome-plated for maximum corrosion protection. Covered key slot prevents corrosion. Features a patented, rugged, pick-proof screw-and-lock mechanism for total security.