Each spring pack is provided with three extra power firing pin springs. P-225/228/229 Spring Pak contains (1) 17 lb., (1) 19 lb. and (1) 21 lb. extra power recoil springs. Factory is 16 lb. P-220 and P-226 Spring Paks include (1) 15 lb., (1) 16 lb., (1) 18 lb., and (1) 20 lb. recoil spring. Factory P220 is 20 lb., factory P226 9mm is 15 lb., factory .357 Sig and .40 S&W are both 20 lb.