The TowSmart Trailer Hitch Ball, Class IV, 2-5/16in Ball, 1-1/4in x 2-1/2in Shank Diameter, 12000lb, 724, Chrome, 1 Each is a key component to create a secure connection between your vehicle and trailer when towing. The heavy-duty construction is durable with a chrome plated finish that is corrosion resistant. The hitch ball provides wrench flats for easy positioning in the X-Mount lock rail system. The lock rail functions as a built-in wrench, preventing hitch ball rotation during installation or removal. The wrench flat design is universal to be used with any standard ball mount.