This Aero Precision Lower Parts kit is a great starting point for finishing your AR-15 Lower Receiver. It includes all of the small parts and components you would typically find in a lower parts kit, but does not include the fire control group, trigger guard or pistol grip. This way you can choose your own grip, fire control group and trigger guard.IMPORTANT: This lower parts kit does not include the fire control group, pistol grip or trigger guard.Includes: Takedown/pivot Spring Takedown/pivot detent Takedown pin Pivot Pin Bolt Catch Bolt Catch Spring Bolt Catch buffer Bolt catch roll pin Safety Selector Safety Selector spring Safety Selector detent Buffer retainer Buffer retainer spring Magazine catch body Magazine catch spring Magazine catch button