Shimano Ultegra CS-R8101 12 Speed Cassette 11-34T SilverThe Shimano Ultegra CS-R8101 12 Speed Cassette has a new tooth profile designed to work with both Di2 electronic and mechanical Shimano drivetrains. The Tooth profile has slightly changed to better accommodate mechanical shifting. The refined 12 step gear combination provides peak efficiency and accelerating performance for every racing situation. Engineered to shift smooth under maximum pedaling pressure. Compatible with both new 12-speed (HG-Spline-L2) and road 11-speed (HG-11) freehub bodies. These cassettes weigh 291g for the 11-30t, and 345g for the 11-34t. Available in gear ranges 11-30t and 11-34t.192790849881