The Advanced Technology AR-15 Crush Washer 5-Pack provides essential spacing and alignment for muzzle devices on .223/5.56 caliber AR-15 rifles with 1/2"-28 threaded barrels.Advanced Technology AR-15 Crush Washer 5-PackCompatible with .223/5.56 caliber riflesFits 1/2"-28 thread pitch barrelsOxide finish for corrosion resistanceFunctions as spacer for proper muzzle device timingPack of 5 washers for multiple installationsEssential for proper installation and timing of flash hiders compensators and other muzzle devices on AR-15 platform rifles ensuring secure attachment and optimal performance.