Midwest Industries SPLP Low Profile Flip Up Rear Sight The Midwest Industries Same Plane Low Profile(SPLP) Rear Sight is a folding, A2-style, dual aperture rear sight that mounts to any flattop AR-15 upper or M1913/Picatinny-style rail. The Midwest Industries back up rear sight uses a detent button to lock the sight in the up or down position. The Midwest Industries low profile flip up rear sight sit much flatter than many back up sights to allow clearance of lower mounted scopes and sights. Constructed of hard anodized 6061 aluminum. Specifications: -Material:6061 Aluminum -A2 style dual aperture -The sight height is .4375" when folded.