Samson Manufacturing Corp. Fixed Rear Sight, Fits Picatinny, Black, Standard Dual Aperture, 6061 Aluminum, Mil-Spec Hardcoat Anodized for Durability 02-00044-01 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.