The MBUS (Magpul Back Up Sight) is designed as a low cost folding back up iron sight.
Ambidextrous spring-loaded mechanism is extremely intuitive and positive.
In the lowered position, it fits under most EOTech and Aimpoint magnifier setups.
The MBUS fits all Picatinny rail equipped weapons, but is specifically tailored to the AR15/M16/M4 platform.
Dual aperature, adjustable for windage.