The ProMag Flip-Up Rear Sight for the AR-15 attaches to any standard 1913 Picatinny rail and can be used as a co-witness iron sight with most red dot and holographic sights, or as a stand-alone sight. This lightweight sight features the standard military A2-style double peep aperture, which allows for a known point of impact. The sight has full windage adjustment; one click of the windage knob provides approximately 0.48 MOA (minute of angle) change when mounted on the full size A4 flat top rifle and about 0.65 MOA on a carbine. The sight is low profile, so that when in the down position it will clear most optics. The sight locks in its upright position and uses a spring loaded release must be depressed to place the sight in the down position. Lightweight polymer construction.