Superlift is proud to offer Superide leaf springs for the Ford F250, F350 Super Duty made here in the USA. The spring rate is designed to match the needs of your particular vehicle by closely evaluating the factory spring rate data. All Superlift springs are made with Spec. 5160 spring steel. These springs have tapered leafs with Teflon inserts to provide the best balance of stability, flexibility and ride qualityLeaf springs are sold individually. Spring bushings and replacement u-bolts are sold separately. The spring bushing kits include polyurethane bushings for two leaf springs. The u-bolt kit includes 4 u-bolts with washers and nuts. The u-bolts have either a zinc or E-coat finish. Superlift is proud of their leaf springs and offers a Limited Lifetime Warranty to offer you confidence in your purchase.