LBE Unlimited REV Flash Hider 5.56mm 223 Cal Black 1/2in-28 tpi Threads Crush Washer. 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 Specifications for LBE Unlimited Flash Hider 5.56mm/.223 Cal: Manufacturer: LBE Unlimited Gun Make: Universal Package Contents: LBE Unlimited Flash Hider 5.56mm/.223 Cal LBE Unlimited ARFH-REV REV Flash Hider 5.56mm 223 Cal Black 1/2-28 Tpi Thread