Adjustable Tactical Sight set and Revolutionary Tactical Rib set for most famous brand semi-automatic and pump shoguns such as Beretta, Benelli, Mossberg, Browning, Winchester, Ithaca, etc... Tactical sight sets fit barrel diameters ranging from .819" to .842" for standard shotguns and .858" to 882" for heavier gauges. Tactical Rib Set fits ventilated ribs from 6mm to 9mm wide. Easily attached by means of screws on each side locking the sight onto the rib. Milling is necessary to fit rear sight.LPA/Fusion