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RBS - Rear polymer back-up sight - Fab Defense - Available in Black, Green, Tan Color

  • $5235

The RBS is an advanced, dual aperture, durable and low-profile auxiliary rear sight. It can be used with any front sight and was designed for more accurate aiming and faster target acquisition. Windage is easily and quickly adjusted without tools.

RBS is readily mounted on any 1913 Picatinny rail, making it ideal for use on M4 / AR-15 / M-16 platforms and on the FAB Defense® K.P.O.S.


Can be used as primary or back-up sight
Ergonomic angel-wing-shaped shroud helps center the image with any front sight, and when used with a matching FAB Defense® FBS Front Back-up Sight, it creates a precise optical tunnel that ensures more accurate aiming and faster target acquisition
Dual apertures are 3mm for longer eye relief mounting, low light, and faster target acquisition; and 1.5mm for shorter eye relief mounting and greater accuracy; each is instantly selectable to match conditions
Low folded profile is smooth and inconspicuous, and will not snag on gear, webbing, or brush
Instant spring-locked deployment mechanism will not slip, break or deform
No tools needed for easy, rapid windage adjustments, with positive detent locking
Made of extremely durable high-grade polymer and metal
Available in Black, Olive OD green, or Desert tan


Weight 30 gr
Width 32 mm
Height 14 mm
Length 52 mm
Height (open / deployed) 42 mm
Length (open / deployed) 30 mm


All 1913 Picatinny rails