The Burris AR-F3 is the simplest, most effective way to mount any FastFire sight on an AR flattop. It allows the FastFire to be mounted at the optimum height, so the red dot can co-witness with flip-up sights. The metal wings protect the lens from impact and unintentional abuse. The lower compartment stores spare battery, open-end wrench and a Torx wrench. Misc Flattop AR-15 Type Scope Mount Model AR-F3 Mount Style Red Dot Optic Mount Finish Black Matte Pieces 1 Series Mount Gun Type Rifle Material Steel Mount Type Picatinny/Weaver Rings Included No