this rail is designed to fit on ventilated shotgun sight rib with a width not exceeding 8.2 mm. This will allow you to fit almost any dot sight. Made of hardened black alloy. 2 steel underside plates and 8 screws secures rail to sight rib. allen keys included. 8 slot 85mm long 21mm wide 5mm base to top (thats sitting on top of the rib to the top of the new rail)