Sprinco Recoil Springs make a significant difference by the management of peak impact forces to the slide/frame interface. Extend the life of your pistol by installing a Sprinco recoil spring system. A secondary, or sub-spring assembly is incorporated onto a heat treated, 17-4PH H900 stainless steel guide rod to cushion the slide to frame impact! All components, including the chrome silicon wire secondary springs, are hand polished to a brilliant finish for reduced friction.