The A2 AR-15 rear site can be used as a co-witness iron sight with most red dot sighting systems, as a stand-alone sight or in conjunction with one of our interface rails. Weighing in at just over two ounces, it features the standard military A2-style double peep aperture which allows for end user known point of impact. The sight has full windage adjustment with the tactile windage knob. One click of the windage knob provides approximately 0.48 MOA change when mounted on the M16A2E4 rifle and about 0.65 MOA on the M4 carbine. Initial zero is set by adjusting the weapons front sight post. It is low profile so that when in the down position, it will clear most optics. The mount body and sight stem are manufactured from billet 6061 T6 aluminum alloy and Type III hard coat anodized in a non-reflective black mil-spec finish to provide combat durability. All steel components are black manganese phosphated per mil-spec. These are the same back up iron sights used by elite armed forces and law enforcement teams world wide.