The new Dura Ace from Shimano is the answer to the question of many profs and ambitious amateurs as to whether and how the current high level of performance could be further increased. Each individual Dura Ace R9100 component is designed to work as efficiently as possible with all other components of the system. This shows the core of Shimano's component-developed-as-a-system philosophy particularly clearly. The result is called SYSTEM SUPREMACY - the superiority of the system over the sum of the individual parts. With the new SHIMANO cassette sprockets, adjustable by the rider, the Dura Ace R9100 allows gear combinations to be adjusted to your driving style and the terrain of your choice. The new lightweight 11-speed cassettes are available in various sprocket combinations, including the new 11-30Z version. Fast, precise and smooth shifting in all situations is guaranteed. Available gradations: 11-12-13-14-15-16-17-19-21-23-25 teeth/average weight: 175 g 11-12-13-14-15-17-19-21-23-25-28 teeth/average weight: 193 g 11-12-13-14-15-17-19-21-24-27-30 teeth/average weight: 211 g 12-13-14-15-16-17-18-19-21-23-25 teeth/average weight: 189 g 12-13-14-15-16-17-19-21-23-25-28 teeth/average weight: 205 g