Gemtech Abyss 5.56mm Silencer CALIBER RATING: 5.56 NATO, 6MM ARC, 5.7X28MM LENGTH: 6.1″ w/o adapter WEIGHT: 14.5oz w/o adapter MATERIALS: 17-4PH Stainless Steel, 6AL4V Titanium SUPPRESSOR FINISH: High-Temp Cerakote MOUNT/MUZZLE FINISH: Armornite, PVD ATTACHMENT: 1.375-24 (HUB), ETM (included) FULL AUTO RATED BARREL RESTRICTIONS: 5.56 NATO: 7″, 5.7X28MM: 3″, 6MM ARC: 7″ LOW BACK PRESSURE DESIGN for greater host reliability and shooter comfort HIGH EFFICIENCY BAFFLE DESIGN for high sound reduction GM-S1 END CAP DESIGN for minimized muzzle flash from the first shot to the last