o Installing Air Lift's LoadLifter 7500 XL Ultimate makes towing and hauling with select Ford F-250 and F-350, single rear wheel, and four-wheel drive a breeze. Adding this air spring kit eliminates many issues associated with towing and hauling, like squat, bottoming out, trailer sway and body roll. The air spring kit is designed with an internal jounce bumper that allows the springs to run safely with zero air pressure. The LoadLifter 7500 XL Ultimate and its design offer 7,500 lbs. of load-leveling capacity, absorbs shock, and are fully adjustable when you are, or aren't, hauling and towing. The LoadLifter 7500 XL Ultimate's air springs are maintenance-free, can run safely on zero air pressure, and are fully adjustable from 5-100 PSI for precise control. Do not exceed the vehicle's gross vehicle weight rating (GVWR).