Decreases Vibration & Stabilizes Sway: Manufactured from microcellular polyurethane, SuperSprings SumoSprings are designed to reduce rear-end sag, decrease vibration, stabilize sway, and soften harsh rebounds Support & Control: Progressive spring with a very soft initial engagement; That means that as more weight added, the harder they get and more they push back, providing support and control when you need it without affecting the factory ride when unloaded Handmade with Care: Every SumoSpring is handmade with care, making each one unique with its own natural characteristics, such as slight color variations and surface bubbles, proof of the craftsmanship that goes into every piece SumoSpring Capacity: The SSR-117-47 has a 1,500 pound capacity when compressed 50 percent; To maintain full memory rebound, the Black SumoSprings should not be compressed beyond 65 percent of their original height Vehicle Compatibility: These Black SumoSprings are specifically designed to fit 2009-2018 F150; Fits 4x4 models only; Do not use on Raptor models