FAB Defense FX-FBS Front Back-Up Sight AR-15/M4/M16 Black Folding

FBS is an advanced, low-profile, durable, auxiliary front sight. It can be used with any rear sight, but has been designed to provide an extreme optical advantage. Its sight pin elevation is easily and quickly adjusted without tools. The FBS is readily mounted on any 1913 Picatinny rail, making it ideal for use on M4 / AR-15 / M-16 platforms. The sight can be used as a primary or back-up sight and the ergonomic angel-wing-shaped front shroud helps center the image with any rear sight. The low fo