This pair of extra-heavy-duty coil springs is designed to provide a 70% increase in load handling capability over the vehicle's nominal spring rate, and offer an easy upgrade for vehicles used in continuous heavy hauling conditions. Custom-engineered to improve ride quality, reduce driver fatigue, and improve handling, they're an ideal replacement for coil springs on many pickup trucks, SUVs, RVs, plow trucks, vans and more. Prefer upgrading to coil springs that aren't as stiff? Check out the lighter version of this spring set that provides a 35% increase in load handling capability over your truck's nominal spring rate.