The Mountmaster AO series has been developed to provide a fast correction to focus and parallax through the adjustment (ao) lenses. Now you can adjust right down to targets that are only 10 yards if required! The AO series feature a match quality 3/8 inch dovetail mount ring. Additionally a recoil stop screw that allows the mount to be secured to powerful airguns without fear of shifting under the sharp recoil of the spring release. Supplied with mildot reticles as standard. Available in illuminated reticle or black.