The shimano dura ace 7900 10 speed cassette a super lightweight 10 speed cassette with a rigid alloy carrier for excellent shifting even under the most demanding gear changes hyperglide sprockets have a computer designed tooth configuration with contoured shift gates resulting in a crisp smooth shift even under load shimano dura ace 7900 10 speed cassette features close ratio gearing allows a more efficient use of energy through finer cadence control largest sproc