The F.A.B. Defense Polymer Flip-Up Front & Rear Sight Sight is designed to deliver intuitive target acquisition by creating an optical tunnel. The smooth design prevents snags and can be used as either primary sights or back up iron sights. These sights easily install on standard Picatinny rails and boasts toolless elevation and windage adjustments, while a positive detent lock locks the sights in the deployed position for reliable performance. Manufacturer model #: FX-FRBSKIT. Durable polymer construction Compatible with standard Picatinny rails Smooth, low-profile design Toolless elevation and windage adjustments Positive detent lock