The Magpul MBUS Front and Rear Sights are low-cost, color injection molded, folding back-up sights. The front sight is adjustable for elevation while the dual aperture rear sight is adjustable for windage. Both sights fit most 1913 Picatinny rail equipped weapons, but are specifically tailored for the AR-15/M16 platform.
Q: Can the front sight be installed on a railed gas block?
A: Front sight cannot be mounted to a railed gas block due to excess heat issues. Front MBUS must be mounted to a railed fore end on the same plane as the receiver rail. Because of this the sight is also not compatible with MOE Hand Guards.