New in non retail packaging, G&P Knights Armament replica RAS II. For use on standard M4A1 carbine (AEG or GBB), mounts over the delta ring so it does not need it's own barrel nut. Thanks for looking, message me with any questions. Tap the pictures to expand and see the whole thing. If I don't reply, please feel free to send another message. Sometimes they don't go through or I miss them. Tap my name to see my other posts!