New tooth profile designed to work with both electronic and mechanical Shimano drivetrains. Tooth profile slightly changed to better accomodate mechanical shifting For Di2 and Mechanical Shifting Systems Refined 12 step gear combination provides peak efficiency and accelerating performance for every racing situation Faster, smoother shifts under maximum pedaling force Compatible with new 12-speed (HG-Spline-L2) and road 11-speed (HG-11) freehub bodies Cassette Body Type: Shimano HG-Spline-L2 Drivetrain Speeds: 12 Range: choose; 11-30t, or 11-34t Weight: 291g. (11-30t); 345g. (11-34t) Color: Silver