FAB Defense FXFBS Flip-Up Front Back-Up Sight – AR-15/M16/M4

The FAB Defense FXFBS is an advanced, low-profile front back-up sight designed for shooters who need a durable, reliable aiming solution on their AR-15, M16, or M4 platform rifle. It works as a standalone primary sight or as a back-up to a red dot or optic, giving you a fast fallback option if your primary sighting system goes down.

Built from high-grade polymer and metal, the FXFBS mounts directly to any 1913 Picatinny rail. Its spring-locked deployment mechanism snaps into position instantly without slipping, breaking, or deforming, and the sight pin elevation adjusts quickly without tools. The ergonomic angel-wing-shaped front shroud helps center the sight picture with any rear sight, and when paired with a matching FAB Defense RBS rear back-up sight, it creates a precise optical tunnel for more accurate aiming and quicker target acquisition.

Key Specifications

• Type: Flip-Up Front Back-Up Sight
• Compatibility: AR-15 / M16 / M4 platforms
• Mount: 1913 Picatinny rail
• Profile: Low folded profile, snag-free design
• Deployment: Spring-locked, instant deployment
• Elevation Adjustment: Tool-free sight pin adjustment
• Construction: High-grade polymer and metal
• Shroud Design: Angel-wing-shaped for centered sight picture
• Weight: 0.16 lbs
• Color: Black

Whether you're running it as a primary sight or a back-up to your optic, the FXFBS gives AR-15 shooters a tough, snag-free option that deploys instantly when you need it. FAB Defense FXFBS Front Back-Up Sight for sale at Loftus Firearms.