The shimano m770 xt cassette 9 speed is a high performance 9 speed cassette hyperglide sprockets have a computer designed tooth configuration with contoured shift gates resulting in a crisp smooth shift even under load close ratio gearing allows a more efficient use of energy through finer cadence control the six largest sprockets are mounted on a lightweight alloy carrier to reduce weight and increase rigidity the sprockets are cut away and drilled to further reduce weight without reducin