Rugged aluminum and steel flip-up front sight regulates with all A.R.M.S. rear sights. Front post is the same width as the standard M16A2 sight post. Easily mounts to a Picatinny receiver rail. Non-snagging lever instantly releases the spring-loaded sight into the ready position. Mfg: A.R.M.S.,Inc SPECS: 5⁄8" (1.5cm) high from rail (folded), 1¾" (4.4cm) high deployed. For proper regulation with A2-type rear sight, must be mounted on a handguard rail or railed gas block that is the same height as the receiver rail.