SAMSON MFG Fixed Rear Sight - A2\n\n- Fixed rear sight\n- Dual aperture\n- Attaches to any 1913 Picatinny rail\n- Co-witness height: M4\n- Stainless steel clamp\n- Accepts aftermarket rear aperture replacements with Mil-spec dimensions\n- Not intended for lower height gas block rails\n- Durable construction and mounting system to stay on zero