The LBE Unlimited AR-15 REV Flash Hider effectively breaks up the muzzle blast from your AR-15 rifle, reducing your flash signature. With an included crush washer, the flash hider can be indexed to assist in controlling muzzle rise and flash dispersion angle. LBE Unlimited AR-15 REV Flash Hider 5.56 NATO/.223 Rem 1/2-28 TPI Specifications and Features: Item Number: ARFH-REV, Caliber: 5.56 NATO/.223 Remington, Thread Pitch: 1/2-28Crush Washer, 3/4″ Wrench Flats, Matte Black Finish