Shimano dura ace 9000 11 speed road cassettesuper lightweight 11 speed hg ev cassette with a rigid carbon and alloy carrier for excellent shifting even under the most demanding gear changes features hyperglide ev 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 largest sprockets are mounted on lightweight alloy and carbon car