FAB Defense FXFBS Front Back-Up Sight AR-15/M4/M16 Flip-Up Black Polymer & Metal

The FAB Defense FXFBS Front Back-Up Sight is a low-profile, spring-locked flip-up front sight purpose-built for the AR-15, M4, and M16 platform. Designed to serve as either a primary aiming solution or a low-profile auxiliary back-up, the FXFBS deploys with a positive spring action and folds flat to keep your primary optic's sight picture completely unobstructed.

The sight mounts quickly and securely on any standard 1913 Picatinny rail, making it a drop-in addition to nearly any flattop AR build. Its construction blends a lightweight polymer body with metal internal components in a non-reflective matte black finish. The low folded profile keeps the sight tucked well below the line of sight when stowed, while the sight tower features an ergonomic shroud to protect against impacts and snags.

A major advantage of the FXFBS is its tool-free windage adjustment, allowing the shooter to quickly and easily zero the front sight without breaking out extra gear. Pair it with a matching FAB Defense RBS rear flip-up sight for a complete co-witnessed back-up iron sight system, or use it on its own alongside a magnified or red-dot primary optic for a reliable offset or co-witnessed aiming option on defensive, duty, and recreational AR builds.

Key Features:

• Flip-up front back-up sight for AR-15, M4, and M16 platforms
• Mounts to any standard 1913 Picatinny rail
• Low folded profile with spring-locked deployment
• Lightweight polymer and metal construction in matte black
• Tool-free windage adjustment for fast, precise zeroing
• Ergonomic shroud protects the sight tower from impacts
• Functions as primary or back-up iron sight