The CMMG AR-15 Lower Receiver Parts Kit includes all the parts you need to get started on your next AR-15 build. Combine this kit with a buttstock kit to complete your lower group. All parts meet or exceed Mil-Spec standard. Kit IncludesBolt CatchBolt Catch PlungerBolt Catch SpringHammer Roll PinTrigger GuardTrigger Guard Roll PinTriggerTrigger SpringTrigger PinDisconnectorDisconnector SpringHammerHammer SpringHammer PinSafety SelectorMag CatchMag Catch SpringMag Release ButtonDetentDetent SpringPivot PinSafety DetentSafety Detent SpringPistol GripPistol Grip ScrewBuffer RetainerBuffer Retainer SpringTakedown PinDetentDetent Spring