This exclusive combo set is designed to kickstart your build with the powerhouse combo of a Stag 10 Assembled Upper and Lower Receiver! Includes: Stag 10 Assembled Upper Receiver Right Handed - Black Stag 10 Stripped Lower Receiver Right Handed - Black Proprietary Port Door Assembly Installed Proprietary Pivot and Takedown Pins NOTE: These receivers feature an Armalite cut and are NOT compatible with DPMS pattern receivers and handguards such as the Aero Precision M5 lineup.