Keep your towing system and its components secure with this Reese Sleeved Receiver Lock Coupler Lock Combo. Includes a barrel-style receiver lock with a sleeved pin that fits a 5/8 or a 1/2 hole size and a coupler lock. Both locks utilize a push-button lock mechanism and a rubber cover to keep the lock clean and protected. Chrome finish. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Trailer Hitches & Accessories.