Dura Ace 10-speed cassette with super light aluminium spider and improved shifting performance. The aluminium spider and the 4 largest titanium sprockets ensure low weight and high stiffness. The revised pinion design further increases shifting precision. The Dura Ace cassette is offered in 8 different sprocket gradations. This means that the optimum gear gradation can be precisely adapted to the respective application. Shimano 10-speed cassettes also fit on Shimano 9-speed cassette hubs, but require a super slim 10-speed Shimano chain!