The Mission First Tactical back up polymer flip up rear sight with windage adjustment mounts onto a 1913 Picatinny rail. A flat head screw driver is required to adjust an infinite MOA. Unlike other backup sights MFT has developed a Shroud that shelters the aperture from debris and impact damage when not deployed. A slim profile allows the sight to sit under all current magnifiers and optics. Manufactured using a specially developed military grade reinforced, super tough polyamide, made in the USA..