Wilson Combat's Custom-Tune Spring Kits are designed to easily and inexpensively improve the action and functionality of your handgun. These quality spring kits feature the finest gun springs available, made from high-tensile spring wire for the finest possible action tuning jobs. Kits include the various springs necessary to assure reliable function, smooth operation, consistency, and long life. The Custom-Tune Spring Kit includes an RP 18 lb. hammer spring, XP firing pin spring, RP 10 lb. and XP 15 lb. recoil springs.