In an effort to keep improving our product line, we have redesigned our Spring Actuated A2 BUIS Back Up Iron Sight, Not only is the action quicker, it still has all of the benefits of our original one and is less expensive too Just like the original, the A2 Spring Actuated BUIS provides the operator with an easytoinstall push button operated AR15 flip up rear sight, The A2 sight stem not only springs into an on target position with just the push of the actuator button, but it also locks solidly into the upright ontarget position, Another push of the button and the lock is released allowing you to set the A2 sight into the locked down position, The sight cannot be folded down without depressing the actuator button located on the left side of the sight base, This totally eliminates the possibility of accidentally lowering the sight, Equipped with the GGG tactile grip windage knob, adjustments are easy and precise, The Spring Actuated A2 BUIS can be used as a standalone sight or in conjunction with one of our interface rails, It can also be used as a cowitness iron sight with most red dot sighting systems, Weighing in at under 2, 4 ounces, it features the standard military A2style double peep aperture which allows for end user known point of impact, No need to retrain with this aperture, The sight has a full range of windage adjustment, 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 solid 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, SKU: TCLGR1169