Dual-rate lowering coil springs improve the handling, ride quality and stance of your early Mustang. StreetGRIP coil springs are CNC cold-wound from high tensile premium steel by then powder-coated for long-lasting, consistent operation. The dual rate designgives you the best of both worlds. The "soft" spring section helps your Mustang to transition over small road irregularitieswith comfort. Asthe vehicle further compresses the spring, such as when encounteringlarge bumps and high cornering loads, the springstransition to the firmer spring rate to support aggressivebump and body roll movement. Using our exclusive test track,RideTechworks closely with Hyperco, its technology partner to develop Mustang-specificspring rates for exceptional performance and comfort.