Contains 1 each FSW 15 lb., A variable recoil spring and 20 lb. hammer spring plus (1) 18 lb., RP hammer spring and (1) XP firing pin spring. These will NOT fit current production Sig models that have the new plastic mainspring housing and stirrup. Mfg: Brownells SPECS: RP = Reduced Power, XP = Extra Power, FSW = Factory Standard Weight.