Gemtech

Gemtech GM-9 Threaded Rear Mounts Caliber - 9 MM Sound Reduction Diameter Length Weight Mount Material Full Auto Rated Finish Thread size 5/8-24 5/8-24 mount is for use with .300 Whisper and .300 Blackout carbines using SUBSONIC ONLY. The Threaded Endcap Adapter to use on GM-9 and MULTIMOUNT suppressors when used with fixed barrel carbines and SMGs.