CNC machined from aluminium alloy with matte oxide finish. No wider than 7.9mm，These rails attach as low as possible on the ribs for a slim profile that provides minimal interference. The principle of installation consists in transverse blades that pass through the holes in the ventilated plate and are attracted by two screws. On the sides of the transition bar has 2 pins, providing additional fixation，don't fit on top of a picatiny rail, please pay attention to the size from pictures. Vent Rib Picatinny Mount Adapter suitable for the IZH-27,MR-153/155, MP-233, TOZ-120, MTs21-12, TOZ-84，which is not fit for TOZ-34.