The Yankee Hill Front Flip Sight Tower features either a round hooded front sight guard that allows for fast and accurate sighting or a standard style front sight guard. The sight base on the Front Flip Sight Tower features all steel construction for superior strength in demanding conditions. The flip sight is easily concealed with the push of a button. When needed it flips up and locks in the deployed position. It is as easy as that!! This sight accepts all standard AR sight posts and hardware (Included). With this setup you get the convenience of a flip front sight with the same weight as a standard AR sight tower. The Front Flip Sight Tower has a two-piece design allowing it to be mounted on firearms with pinned and welded muzzle accessories. It mounts easily and securely with four cap screws using a 7/64 inch Allen wrench. These gas blocks have a bore diameter of .750 inches.