An AR-15 Upper Receiver Sear Cut Insert to keep AR-15 from going into Full Auto Mode. The insert is hard coat anodized. Great for areas with these specific restrictions! Mfg: Brownells
Dark Storm Industries DS-15 Typhoon AR-15 5.56 14.5inch Upper Receiver w/Pin and Weld Mid Length 1-7 Twist 1/2x28 Firestorm Compensator Cerakote Flat Original price was: $1,039.00.$919.95Current price is: $919.95. 
Moriarti AR-15 5mm NATO 5 inch Upper Receiver Medium Micro Length 1-5 Twist 1/2x28 A2 Flash Hider Nitride Original price was: $349.95.$229.99Current price is: $229.99. Ar-15 Upper Receiver Insert – Brn Ar-15 Upper Receiver Insert, Black
Original price was: $8.99.$3.99Current price is: $3.99. 