Rear Sight Rail Mount 100mm Picatinny Weaver 20mm Scope Mount Base For Hunting Red Dot Optics Accessories Rear Sight Scope Mount Rail Picatinny Weaver For Optics Feature: -Fast and easy installation. -Mount on standard 20mm weaver base -Constructed of Aluminum Quick 1 step installation. Ultra light weight and low profile red dot scope mount for rifles Reference aiming dots on rear to use scope mount rail as backup iron sight Replaces stock rear sight assembly and installs in seconds with no gunsmithing or permanent modification to rifle required Scope mount rail allows you to use fixed sight. Specification： 1.Customizable level adjustment (up/down, left/right) . 2.Hardcoat anodized 6061 aircraft aluminum. 3.Recommended for use with low profile red dot. 4.Integrated back-up rear sight. 5.3X M3 countersunk hex screws. 6.1X M3 oval head screw.