Aero Precision Lower Parts Kit, 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, 4-40 Set Screw, Buffer Retainer, Buffer Retainer Spring, Magazine Catch Body, Magazine Catch Spring, and Magazine Catch Button, Does Not Include the Fire Control Group, Pistol Grip or Trigger Guard APRH100385C