This Back Up Polymer Flip Up Rear Sight from MFT is a great addition to any AR sighting system. It mounts to any standard 1913 Mil-Spec Picatinny Rail and is adjustable for windage. When folded down and not in use it’s shrouded and sheltered to protect the apertures from debris and impact. It has a slim no snag low profile. Dual peep same plane apertures are ready to give you the perfect co-witness with your reflex sight!