The MBUS (Magpul ? Back-Up Sight) is a low-cost, color injection-molded, folding back-up sight. The MBUS Front Sight is adjustable for elevation and fits most 1913 Picatinny-railed hand guards, but is specifically tailored to the AR15 / M16 platform.An elevation adjustment tool is included, but most aftermarket A2 front sight adjustment tools may be used as well.Made in the USA.