This mount attaches to the barrel of your AR type firearm. It is designed to accept picatinny style attachments. Its three mounting surfaces allow you to attach accessories such as flashlights, laser sights, grips, etc. Clearance is provided for a bayonet lug. Mounts to barrels with diameters of .730 and .750 (required bushings included) with supplied cap screws. Made from aircraft quality aluminum and hardcoated to mil. specs.