Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC, and to all U.S. Military APO/FPO/DPO addresses.

Enjoy our FREE RETURNS

We want to ensure that making a return is as easy and hassle-free as possible! If for any reason you are not satisfied with your purchase, simply return the item within 30 days of receipt, and we'll cover the cost of return shipping. Learn more about our Return Policy.

Shopping Cart
Questions & Answers
Can you adjust elevation Manufacturer Answer

No, you can adjust elevation on the front sight

by FAB Defense, Manufacturer, July 2, 2025
Will this sight work with a magpul front sight? Expert Answer

The FAB Defense Rear Polymer Flip-up Rear Sight is compatible with standard height front AR sights. So yes, it will work with the Magpul Flip up front sight.

by Hunter, Gear Expert, April 7, 2022
Customer Reviews
Helpful Positive Review
Not a bad sight by G, June 19, 2019
Not a bad sight.. Was looking for something different.. But I'd like it better if it was a button flip up like magpul.. It's a manual flip.. But looks great and works as it should.. Would recommend to others
2/2 found this helpful
Helpful Negative Review
Rear sight by J Wood., November 4, 2021
It did not come with the Allen wrench to sight it in. And I am very much not happy with my order. How am I going to sight in the product you sent me without the tools that should have came with the package?
1/28 found this helpful
Most Recent Reviews
not good sight by Dak, May 16, 2021
The issue was that the rear sight shifted too far to one side on the rail when tightened even the slightest bit, causing near-maximum windage to find a zero (it is not an issue with the weapon). There is no spring assist either. These must be manuall...
Read More...
3/8 found this helpful
Most Recent Reviews
fab front/rear sights by Mike O, Verified Owner, August 22, 2024
Nice, well made sights. Im very happy wiith these sights. Easy adjustments. Will buy more.
Most Recent Reviews
Quality polymer sight by E, Verified Owner, May 19, 2024
Quality seems to be on par with magpul. Sights are manual flip up and down and do not lock into place. Haven’t had any issues with them staying locked in place so I don’t see this as an issue at this point in time. Would buy again for bargain polymer...
Read More...
Most Recent Reviews
These come in at a great value in my opinion. I was a little hesitant at first because there is no manual locking mechanism for the sight in the upward position, meaning I'd like to have to push a button to fold them down, but my worries were elimin...
Read More...
Read All 9 Reviews

We've got an AWESOME deal for you!

Blazin' Deal
Prices have been cut drastically on select models of this product as part of a special offer. These prices are so low that there's no double-dipping with coupons or any additional discounts - sorry about that. This offer won't last long, so don't miss out!
In Stock
4 Models Available

Show with deals only:

Blazin' Deal
Color
All
Rear Sight Color
All
Search

Product Info for FAB Defense Top Mounted Deployable Rear Sight

The FAB Defense Polymer Rear Sight can be used as both a primary or back-up sight to your current optic. FAB Defense designed these AR 15 Parts with ergonomic angel-wing-shaped shrouds that help center the image with any front sight so that you can accurately use these in conjunction with a front back-up sight or other optic. With an instant spring-locked mechanism for deployment, the FAB Defense RBS will never slip, break, or deform, offering outstandingly reliable performance in the field. Equip the FAB Defense Rear Back-Up Sight on your weapon today for precise views down range every time.image

Specifications for FAB Defense Top Mounted Deployable Rear Sight:

Manufacturer: FAB Defense
Condition: New
Sight Position: Rear
Gun Model: M16, M4, AR-15
Gun Make: AR Platform
Fabric/Material: Polymer
Height: 14 mm
Length: 52 mm
Illumination Type: Non-Illuminated
Illumination Color: None
Hand: Ambidextrous

FAB Defense Polymer Rear Sight, 1S0-IRN-RPFUS

  • 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

Package Contents:

  • FAB Defense Top Mounted Deployable Rear Sight

FAB Defense Top Mounted Deployable Rear Sight Orderable Models

List of Orderable Models

  • FAB Defense OPMOD Rear Polymer Flip-up Rear Sight, Grey , MPN: FX-RBS-OPMOD Grey-KIT2023 , Code: 1S0-IRN-RPFUS-FX-RBS-OPMOD-Grey-KIT2023
  • FAB Defense Top Mounted Deployable Rear Sight, Black, FX-RBS , MPN: fx-rbs , UPC: 7290105941992 , Code: 1S0-IRN-RPFUS-FX-RBS
  • FAB Defense Top Mounted Deployable Rear Sight, Flat Dark Earth, FX-RBST , MPN: fx-rbst , UPC: 7290105947574 , Code: 1S0-IRN-RPFUS-FX-RBST
  • FAB Defense Top Mounted Deployable Rear Sight, Olive Drab Green, FX-RBSG , MPN: fx-rbsg , UPC: 7290105947567 , Code: 1S0-IRN-RPFUS-FX-RBSG
Compare (0)