Fitment: For F-250 XL, XLT, Lariat, and Ranch models with 4WD or RWD configuration, model years 2005–2007.Also fits F-250 Base and Super Duty models from 1999–2004.Compatible only with trucks equipped with B&W Hitch models 1105 or 1199R installed in the 49-inch position.Fits many 3/4-ton and 1-ton pickups or vans with leaf spring rear suspension. Package includes: 2 air springs Air lines Schrader valve Mounting bracket Hardware Capacity: up to 5, 000 lbs per axle Spring type: Leaf Placement: Rear Features: Maintains proper ride height Reduces rear bouncing when towing Prevents main springs from sagging under constant load compression Assists suspension when towing or hauling heavy loads Two adjustable secondary air helper springs provide leveling support for vehicles with leaf springs