The Midwest Industries .30 Caliber AR-10 Muzzle Brake has a three chamber design that significantly reduces muzzle rise. Durable tool steel construction with a Manganese phosphate finish for corrosion resistance.Features: 5/8x24 thread pitch Three chamber design Tool steel construction Manganese phosphate finish Crush washer included Made in the U.S.A. Lifetime Warranty Weight 4 ozMidwest Industries is a quality manufacturer of tactical weapons accessories. Their goal is to manufacture the highest quality parts at affordable prices backed by a lifetime guarantee.