Trimax Razor RP Key Receiver Lock Set -Features hardened steel and provides instant security for your camper, boat or trailer by securing your vehicle receiver hitch. Features patented 1/4 turn technology that cannot be false locked. A receiver pin is used to secure the receptacle part of a trailer hitch (attached to a vehicle) to inserts such as ball mounts, drawbars, accessory carriers or ornamental receiver plugs. Pin Size: 1/2" x 3-5/8"Pin Size: 5/8" x 3-/12"