F.A.B. Defense Flip Up Front and Rear Sight Set, Fits Picatinny Rails, Polymer, Black FX-FRBSKIT FAB Defense manufacturers and distributes unique weapon accessories designed for combat in the most extreme environments. With a workforce consisting of real world operators with real world combat experience you know FAB Defense has the experience necessary to offer you the finest gear available on the planet. You're your life depends is on the line gear up with FAB Defense products. FAB Defense has a flip up sight set that is designed to help you quickly center your target in the sight picture by creating an optical tunnel. The smooth design helps prevent snags and can work as primary sights or back up. Easily installs on Picatinny rails and has tool less elevation and windage adjustments. Sights have a positive detent lock in the deployed position. Front sight not made to be mounted on a gas block.