The Husky Towing 5th wheel lock installs on the king pin, which prevents it from being coupled to another 5th wheel hitch. Specifications•Compatibility: Fifth Wheel/ King Pin Coupler•Style: Surround Lock•Pin Size (IN):5/8 Inch•Finish: Chrome Plated•Color: Yellow/ Silver•Material: Steel•Quantity: Single Husky Branded Replacement Parts Support The Original Product Warranty | Husky Towing Trailer Coupler Lock