The Class IV Tri-Ball Trailer Hitch Ball Mount with Hook is a receiver hitch accessory consisting of three trailer hitch balls and a shank. It provides three permanently affixed hitch ball sizes, eliminating the need to remove and install different hitch balls or ball mounts. It features a hook that can be used for attaching chains, cables or ropes. Class IV mounts are great for towing very large campers, large boats and yachts, and trailers carrying commercial construction equipment. While these are common uses for this class, it is important that you know the total weight of the trailer and its contents, and that you do not exceed the recommended maximum towing capacity determined by your vehicle manufacturer.