Tacticool22 offers high-quality, precision machined black AR-15 1/2" crush washers for AR-style rifles, which are a perfect replacement or upgrade for existing parts to ensure correct alignment of flash suppressors, compensators or muzzle brakes. These crush washers have been re-engineered for a better-looking assembly and improved fit, and will look great on any firearm. The major diameter of these washers is 11/16 or .688. The standard diameter of a barrel is .7 at the muzzle. These will fit on any 1/2 thread, no matter the TPI. They ensure the proper torque because they crush at the correct specifications, then they act like a lock washer to keep end-of-barrel accessories such as muzzle brakes from loosening. Features and Benefits Diameter: 11/16 or .688 inches. Blued to U.S. military standard, Mil-Spec: C13924BAM1, Class 1, Grade A. Made from the finest U.S. steel. Over one full turn of adjustment available for proper indexing. Precision machined (not stamped). Designed, developed, and manufactured in the USA.