High performance 10 speed dyna sys cassettehyperglide sprockets have a computer designed tooth configuration with contoured shift gates resulting in a crisp smooth shift even under loadclose ratio gearing allows a more efficient use of energy through finer cadence controlsix largest sprockets are mounted on lightweight alloy carriers to reduce weight and increase rigiditysprockets are cut away and drilled to further reduce weight without reducing rigiditychrome plated finish offers hard wearing