The Air Lift LoadLifter 5000 adjustable air spring kits, No. 57233 and LoadLifter 5000 Ultimate adjustable air spring kits, No. 88233, work with the vehicle's existing suspension to deliver up to 5,000 lbs of leveling capacity. The air springs eliminate sagging and bottoming out when towing or carrying heavy loads, while providing a safe, comfortable ride. LoadLifter 5000 Ultimate offers all the benefits of the LoadLifter 5000, but its exclusive internal jounce bumper provides added shock absorption and extra protection for heavy loads. The jounce bumper also allows the air springs to be safely operated with zero air pressure. These offerings are now available for 2013-2016 Ram ProMaster 1500, 2500 and 3500 model rear-wheel- drive vehicles.