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  1. Excellent Sights!
    I really like the style of these sights more than the standard Magpul flip-up sights. They work well, have lots of adjustment and are priced right. FAB Defence is no slouch, and I expect these will last a lifetime. The fit and work well on the rifle I bought them for. A+!

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FAB Defense Back-Up Sight (Rear) - Black

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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 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 drab green, or desert tan
  • Made in Merica by the Donald himself 
  • Dimensions Closed:  52× 32 ×14 mm (L × W × H)
  • Dimensions Open:  30× 32 ×42 mm (L × W × H)
  • Weight: 30g


You get:

  • (1) Rear sight

    Compatible with:

    • All 1913 Picatinny rails
    • Picatinny / weaver rails 

    Installation Difficulty: 

    Tools required: None

    Installation notes: Pretty straight forward 

    Manufacturer's model number: RBS