The CURT weight distribution hitch is a specialized towing system that provides improved vehicle and trailer control by leveling the trailer and more evenly distributing its tongue weight across the trailer's and vehicle's axles. Weight distribution hitches are commonly used on travel trailers and campers but can also be applied to other large loads. CURT WD hitches come with a 2" x 2" shank and are compatible with class 3, 4 and most 5 trailer hitches, including Xtra Duty and Commercial Duty (2-1/2" replacement WD shank may be required), as well as some RV trailer hitches. While a weight distribution hitch will increase the gross trailer weight capacity of most trailer hitches, the vehicle's weight carrying capacity must be taken into consideration before towing a heavier trailer (NOTE: Never exceed the lowest weight capacity of any towing component). This trunnion bar weight distribution hitch features a heavy-duty formed head and square spring bars constructed from forged steel. It offers a gross trailer weight capacity up to 8,000 lbs. and a tongue weight capacity of 800 lbs. It also includes hook-up brackets, spring bar safety chains and a pin and clip. To protect this hitch from scratching, chipping, rust and UV damage, it also comes with a durable black powder coat finish. A trailer ball must be purchased separately.