The Shimano Dura-Ace CS-R9200 12-Speed Cassette is a super lightweight 12-speed HG+ cassette with a rigid carbon and alloy carrier. Built for excellent shifting even under the most demanding gear changes.Shimano Dura-Ace CS-R9200 12-Speed Cassette FeaturesHyperglide+ sprockets have a computer designed tooth configuration with contoured shift gates, resulting in a crisp smooth shift even under loadClose ratio gearing allows more efficient use of energy through finer cadence controlThe largest sprockets are mounted on lightweight alloy and carbon carriers to reduce weight and increase rigidity5 largest sprockets are made from titanium to reduce weight without sacrificing strengthSprockets are extensively cut away and drilled to further reduce weight without reducing rigidityNickel-plated finish offers hard wearing resistance to corrosionAlloy cassette lockringFor Super Narrow 12-speed chains