With a rear ring that's positioned 1" forward, the Aero Precision Ultralight Extended Scope Mount offers better eye relief without unnecessary bulk. It features a cross-slot keyway that provides top-notch recoil protection. Designed for upper receivers with Mil-Spec 1913 Picatinny rails. Rugged 6061 T6 extruded aluminum construction with anodized black finish. "Ultralight" design delivers 1 of the lightest mounts in the industry. Scope ring: 1".