The MagPul Back Up Sight (MBUS) Flip-Up Front Sight is a durable, inexpensive Back Up Iron Sight option specifically tailored for the AR-15 platform. Constructed of high impact polymer, the sights are lightweight, unobtrusive, and capable of withstanding harsh environments and rough handling in the field. The Flip-Up Front Sight is spring loaded, popping up instantly when activated by pressing down on either of its side levers or from the top. The sight remains upright under spring and detent pressure, folding only when deliberately stowed by the shooter or in the case of a jarring impact to prevent damage. The MBUS clamps to any standard Picatinny railed handguard, providing the same height-over-bore as a mil-spec A2 fixed front sight. The product-improved Gen 2 MBUS Front Sight features a slimmer profile for greater optics compatibility when in the folded position, while the front sight post now incorporates a spring lock for consistent elevation adjustment. MBUS Front Sights CANNOT be mounted to a railed gas block due to the extreme heat generated during firing. The MBUS Front Sight must be mounted to a railed handguard on the same plane as the receiver rail. MBUS front sights are not compatible with MOE Handguards.Specifications and Features: Compatible With: AR-15 Country of Origin: United States of America Material: Polymer