The Gemtech GM-45/Blackside Threaded Mount Adapter features 1/2x28 threading and enables the use of GM-45 and Blackside suppressors on fixed barrel weapons.Gemtech GM-45/Blackside Threaded End Cap Adapter1/2x28 thread specification for secure mountingCompatible with GM-45 and Blackside suppressorsDesigned for fixed barrel weapon applicationsMatte finish for durability9MM caliber ratedEssential accessory for expanding suppressor compatibility to fixed barrel firearms. Note: GM-45 and Lunar-45 suppressors are rated for 300 Blackout with subsonic ammunition only.