REESE Towpower InterLock ball mounts have a patented hex design which allows for a one-wrench tightening system when combined with a REESE InterLock hitch ball. It makes for installing the hitch ball more efficient, and prevents marring of the hitch ball. It is not limited for use with the InterLock hitch ball, and can be used with any standard hitch ball. Ball Mount Specs: Part Number 21900 Brand Reese Towpower Finish Black Powdercoat Towing Capacity 3500 lbs Tongue Weight Capacity 350 lbs Ball Diameter 3/4" Drop 2-1/2" Rise 2" Thank you for choosing Reese the most powerful name in towing industry bar none. Manufactured by the same people that brought you Draw-Tite and Hidden Hitch all of our products come with standard lifetime warranty and support. Our custom hitches mount easily on your Car Truck Van SUV and RV.