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. Weighing in at just over two ounces, 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 A3 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. The sight body and stem are machined from T6 aircraft grade aluminum, then type III hard anodized. Steel parts are CNC machined, then black phosphated per mil-spec.