The AAC BlackOut Flash Hider 90T SR Series is an extremely efficient design that effectively eliminates muzzle flash even on short barrels. The open-end 3-prong design of the BlackOut is inherently stronger than 4-prong units and is not subject to the wear and erosion commonly encountered with closed-end designs. All AAC Blackout flash suppressors are machined from high strength aerospace steel alloy and coated in a hard durable corrosion resistant SCARmor finish.Rocksett Included