Wilson combat's 11 lb.Recoil spring full size 5" 9mm or.38 super shooting target ammunition with a power factor of 125 000 to 135 000 (velocity x bullet weight = power factor) average service life 20 000 rounds.*note- this is the standard recoil spring we install in our full-size 9mm pistols.Recoil springs are made combat tough to repeatedly take a pounding yet show remarkably consistent performance every time a round is fired.Keeping a fresh recoil spring in your pistol will dramatically reduce the pounding your slide and frame receive.Finish: BlackType: Recoil SpringModel: Recoil SpringSize: Full SizeMaterial: Chrome Silicone Steel