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.

Features:
Spring loaded flip up sight
Easily activated from either side or by pressing the top
Protective wings shield the spring-locking A2 front sight post
Polymer construction provides light weight and resists abuse
Detent and spring pressure keeps sight in place but allows for unobstructed folding under impact