The Shimano Ultegra CS-R8101 12-Speed Cassette features a new tooth profile designed to work with both electronic and mechanical Shimano drivetrains. The tooth profile has been slightly changed to better accommodate mechanical shifting. This cassette is suitable for both Di2 and mechanical shifting systems. It offers a refined 12-step gear combination that provides peak efficiency and accelerating performance for every racing situation. The cassette provides faster, smoother shifts under maximum pedaling force. It is compatible with new 12-speed (HG-Spline-L2) and road 11-speed (HG-11) freehub bodies. The Shimano Ultegra CS-R8101 12-Speed Cassette is available in two range options: 11-30t and 11-34t. The weight of the cassette varies depending on the range option, with the 11-30t option weighing 291g and the 11-34t option weighing 345g. The cassette is available in a silver color.