This gas block is of an all steel construction for superior strength in demanding conditions. The flip sight is easily concealed with the push of a button and locks in the deployed or closed position. This sight accepts all standard AR sight posts and hardware. With this setup you get the convenience of a flip front sight with the same weight as the standard AR sight tower. This sight's two-piece design allows it to be mounted to firearms with pinned or welded muzzle accessories. It mounts easily and securely with four caps screws. Features include a standard bayonet lug and sling mount. By Yankee Hill Machine.