GEM GM-45 Rear Piston Lid 578-

Gemtech Piston for GM-45, Lunar-45 and Blackside-45 LID (.578-28) Caliber Sound Reduction Diameter Length Weight Mount Material Full Auto Rated Finish Thread size .578-28 Can also use on 40 caliber and 9mm pistols. All options can be installed in the field without the use of tools.