Another company releasing their own set of polymer backup sights as it seems to the trend nowadays and also helpful as polymer will help reduce the weight rather than using metal. FAB Defense have released their FBS and RBS Backup sights and are fully adjustable. These can fit all 1913 Picatinny rails and made for the M4 / AR-15 / M-16 platform and the K.P.O.S.

FAB Defense FBS

"The FBS Front polymer Back-up sight is a cutting edge, low-profile, tactical back-up sight.

The FBS front sight is elevation adjustable and can be mounted on all 1913 picatinny rails, but is specialty made for the M4 / AR-15 / M-16 platform and the K.P.O.S.

Advantages:

• Very low profile & slim design
• Can be used as primary or back-up sight
• State-of-the-Art ergonomic & ambidextrous design
• All manual configuration, no tools needed for elevation adjustments
• Durable high grade polymer & metal construction
• Spring based locking mechanism - will not break or deform

Compatibility:

• All 1913 Picatinny rails."

FAB Defense RBS

"The RBS Rear polymer Back-up sight is a cutting edge, low-profile, tactical back-up sight.

The dual aperture RBS rear sight is windage adjustable and can be mounted on all 1913 picatinny rails, but is specialty made for the M4 / AR-15 / M-16 platform and the K.P.O.S.

Advantages:

• Very low profile & slim design
• Can be used as primary or back-up sight
• State-of-the-Art ergonomic & ambidextrous design
• All manual configuration, no tools needed for windage adjustments
• Durable high grade polymer & metal construction
• Spring based locking mechanism - will not break or deform

Compatibility:

• All 1913 Picatinny rails"