Hellwig 11-21 Ford F-250 Load Pro- Up To 3500lb Level LC 4 Leaf Stack Helper Spring w/o Mounting KitThe Hellwig LP 35 Helper Spring set the standard for all other aftermarket helper springs. Featuring a Fulltime Spring Rate design it is the workhorse of the Hellwig Spring line. This is ideal for fleet applications or vehicles that consistently carry a heavy load day in and day out. ATTENTION: MUST PURCHASE LP MOUNTING KIT FOR INSTALLATION. IF EQUIPPED WITH FACTORY CONTACT OVERLOAD SPRINGS, CHECK VEHICLE FITMENT ABOVE FOR SPECIFIC INFORMATION ON YOUR