The Emergency Rear Sight (ERS) is a folding, A2-style, dual aperture rear sight that mounts to any flattop AR-15 upper or M1913/Picatinny-style rail. It locks firmly in the up or down position via a detent button, ensuring positive activation. Windage knob is identical to that used on the M16 A2 rear sight. Constructed of hard anodized 6061 aluminum. Technical Information Material:6061 Aluminum Notes:
