FAB Defense FXRBS Rear Flip-Up Sight – Black

The FAB Defense FXRBS is a low-profile folding rear sight designed for AR-15, M16, and M4 platforms. It can serve as a primary or back-up sight and mounts to a 1913 Picatinny rail.

A wing-shaped shroud helps center the sight picture with a compatible front sight, while the folding design presents a smooth profile when lowered. The dual-aperture system and spring-locked deployment mechanism support adaptable use across changing sighting conditions.

Key Specifications

• The sight is designed for AR-platform firearms, including AR-15, M16, and M4 configurations.
• The mounting interface fits a 1913 Picatinny rail.
• The rear sight uses dual apertures for different sighting conditions.
• The apertures measure 3mm and 1.5mm.
• The sight features tool-free windage adjustment with positive detent locking.
• The deployment system is spring-locked.
• The folded design provides a low profile to help reduce snagging on gear, webbing, or brush.
• The construction combines polymer and metal.
• The finish color is black.
• The product type is a folding rear sight.

With its compact folded profile, selectable apertures, and straightforward adjustment system, the FXRBS provides a practical rear-sight option for AR-platform setups where dependable, adaptable sighting equipment matters.