The Colt AR-15 Lower Receiver Parts Kit contains high quality components for the AR-15 made to strict military specifications. This genuine Colt product will provide excellent fit and reliable function in your AR series rifle and is perfect for upgrading existing components or replacing worn or broken parts. IncludesBolt CatchBolt Catch PlungerBolt Catch Roll PinBolt Catch SpringBuffer RetainerBuffer Retainer SpringDisconnectorDisconnector SpringHammerHammer PinHammer SpringMagazine CatchMagazine Catch ButtonMagazine Catch SpringA2 Pistol GripPistol Grip Lock WasherPistol Grip ScrewPivot PinPivot Pin DetentPivot Pin Detent SpringSelectorSelector DetentSelector Detent SpringTakedown PinTakedown Pin DetentTakedown Pin Detent SpringTriggerTrigger GuardTrigger Guard Roll PinTrigger PinTrigger Spring