Energetic Armament FEROX, 5.56 Caliber Suppressor, 12.5 Ounces, 5.9 Length, 1.63 Diameter, Stainless Steel Construction, 1/2-28 RH Direct Thread, Compatible with Other Mounting Hardware, Nitride Finish, Black EA13 Utilizing 17-4 Stainless Steel heat treated to the H900 condition, the Ferox is engineered to be ultra strong without sacrificing durability. Developed specifically for 5.56mm platforms; particularly for short and mid barrel lengths optimizing low back pressure and excellent sound suppression.