The Blackout flash suppressor is the most efficient design available. It has been military tested and selected. The proprietary features eliminate muzzle flash, even on CQB-length barrels. The Blackout is inherently stronger and more impact resistant than four-prong designs, while not being subject to the rapid erosion of closed-ended units. A high-strength, corrosion-resistant aerospace alloy and ultra-hard SCARmor finish provide the highest level of durability. This non-silencer mounting design is for barrels with 5/8" (.625") of exposed muzzle thread. The 1/2-28 flash hider adds 1.60" to the OAL of the barrel, making 14.5" barrels 16.1" when the flash hider is pinned and welded.