The AR-15 Flip-Up MBUS Gen 2 Front Sight by Magpul is a low-profile, polymer backup sight that mounts on a flattop and deploys quickly with a finger touch.
It's designed to avoid snagging and features a spring-loaded ambidextrous release mechanism, requiring less than 1" of Picatinny rail space.
The front sight provides standard A2 iron sight height over bore and must be mounted on the same plane as the receiver rail for accurate alignment with the rear sight.