Lightweight integrated scope mount system for the AB3 rifle, unitized base and ring, 7000 series aluminum. AB3 only. Browning's Integrated Scope Mount System unitizes the ring and base into a single, ultra-rigid unit. Machined from 7000 series aluminum alloy, they eliminate alignment problems and the possibility of a loose connection between the base and ring. They are available in .400" Standard height, .500" Intermediate height and .600" High height versions to fit your needs.