This is a Samson Manufacturing Corp. Sight known as the Fixed, model FXR-A2.
Samson fixed sights are the most robust fixed combat sights on the market. Accepts all aftermarket rear aperture replacements with Mil-spec dimensions. It is not intended for lower height gas block rails. The durable construction and solid mounting system guarantees you to stay on zero.
Features:
Fixed rear sight
Dual aperture
Attaches to any 1913 picatinny rail
Perfect (M4) co-witness height
Stainless steel clamp
