The MBUS is the first of its kind: a sight designed as a low-cost, color injection molded, folding back-up sight. The MBUS fits all Picatinny rail equipped weapons, but is specifically tailored to the AR15/M16 platform. Adjustable for elevation. This is the REAL STEEL version. Don't be fulled by others trying to sell the airsoft version and passing it as the real steel version.