The GGG A2 AR 15 rear sight is our number one selling Back Up Iron Sight BUIS, It provides the operator with an easytoinstall and easytooperate flip up rear sight, and includes the all important locking detent, Besides providing a low profile ready to go BUIS when you need it, features include a tactile Ergonomic windage knob, a counter sunk crossbolt to eliminate the possibility of snags, and streamlined body, The A2 sight is always at the tactical ready once placed in the up position, The sight cannot be folded down without depressing the spring assisted detent release button located on the left side of the sight base, This totally eliminates the possibility of accidentally lowering the sight, The A2 AR15 rear sight can be used as a cowitness iron sight with most red dot sighting systems, as a standalone sight or in conjunction with one of our interface rails, Weighing in at just over two ounces, it features the standard military A2style 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 nonreflective black milspec finish to provide combat durability, All steel components are black manganese phosphated per milspec, These are the same back up iron sights used by elite armed forces and law enforcement teams world wide, SKU: TCLGR1168