These are for those who demand top stability. Totally integrated ring and mount system. Browning's T-Bolt integrated scope mount system unitizes the ring and base into a single, ultra-rigid unit. Machined from 7000 series aluminum alloy. This eliminates alignment problems and the possibility of a loose connection between the base and ring. Features: Machined from 7000 series aluminum for high strength and durability The integrated design eliminates alignment problems and the possibility of a loose connection between bases and rings