The shimano xtr m9000 11 speed cassette is the lightest 11 speed dyna sys cassette available however it is much more than just a light weight option for the racers everything about the shimano mtb cassette has been designed in a way to get the absolute most from the minimal amount of material that has been used hyperglide sprockets feature a unique tooth configuration with contoured shift gates producing an incredibly smooth shift even under heavy stress extensive cutting and dril