AR-15 A2 Flash Hider 1/2″-28 Threads (5.56/.223) Longitudinal ports help minimize the blinding effects of muzzle flash in low light for improved target acquisition during day and night operations. Screw-on design for threaded barrels only. Includes crush washer for proper timing of flash ports. This  5.56/.223 model has five ports and no ports on bottom to minimize recoil allowing the shooter the quickest possible target reacquisition. Comes with the Barrier Defense lifetime warranty! ****Know your states laws when purchasing gun parts.****