This all-steel sight is easily installed on any Ruger-Style base. Includes two aperture discs, one 0.093" diameter and the other 0.125" diameter. Fully adjustable for windage and elevation. Adjustment wrench included. Comes complete with two apertures (.093" and .125").Notes: Since all firearms shoot slightly different, first install this rear sight and shoot using the stock front sight before changing it. Owners of the Mini-14 and Mini-30 generally use the stock front sight, while 77/22s sometimes need a higher front sight.