FAB Defense AR-15 Iron Sight Set Flip Up - FRBS-B
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FAB Defense
Overview
The FAB Defense AR-15 Iron Sight Set Flip Up - FRBS-B is a pair of folding iron sights designed for quick deployment and reliable performance. Made from durable polymer, these sights provide a lightweight option that won’t add unnecessary bulk to your rifle while maintaining a solid sight picture. This set is commonly found in mid-length gas system builds chambered in 5.56 NATO, making it a practical choice for a variety of uses.
Specifications
Available Merchants(7)
Prices checked
Price Alert
October 2026 on GunPartPicker
FAB Defense AR-15 Iron Sight Set Flip Up - FRBS-B ranked #23 of the 86 iron sights builders added on GunPartPicker in October 2026. Builders have added it to their builds on GunPartPicker. Since April 2026, it ranks #22 of the 170 iron sights builders have added. Builds with this iron sight are mostly chambered in 5.56 NATO (61%, then .308 Win 17%), mostly on mid-length gas (92%, then pistol-length 8%), and mostly AR-15 (82%, then AR-10 18%).
Availability is good: it was in stock at one retailer or another nearly every time we checked in October 2026, and today 4 of the 7 retailers we track have it in stock. It dipped to $69.49 at Optics Planet for a stretch in October 2026, well under its usual $84.99, so sales do come around. Buying today, the lowest price is $83.99 at KY Gun Company, above October's low of $69.49, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
Not sure which iron sights to pick?
We ranked every iron sights by how often it shows up in real builds on GunPartPicker.
Read the guide: AR-15 Iron Sights Guide →Frequently Built With
The part most often added in each category by the builds that include this one
Smith & Wesson M&P15 Complete Lower 5.56x45mm/.223 Remington, Black - 812002
Battle Arms Development Workhorse Barreled AR-15 Upper Receiver - M-LOK - 16"
Daniel Defense Collapsible Mil-Spec Buttstock, Brown - 21-091-04179-011
Holosun HS510C HUD Solar Powered Circle Dot Sight
Bravo Company M16 Bolt Carrier Group Black
Fortis SHIFT Vertical Grip - M-LOK
Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
PlatformBased on real build data showing which platform (AR-15, AR-10, AR-9) builders pair with this product.
CaliberBased on real build data showing which calibers builders choose alongside this product.
Gas SystemBased on real build data showing which gas system lengths builders use with this product.
Builds Featuring This Part
See all builds →Builds in the community that include the FAB Defense AR-15 Iron Sight Set Flip Up - FRBS-B
| Build | Parts | Total |
|---|---|---|
 | 28 | $2650.32 |
 | 16 | $2733.43 |
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