The Shimano ULTEGRA 12-speed HYPERGLIDE+ road cassette is designed for smooth shifting while climbing, sprinting, and enjoying bike rides. Larger cogs make the drivetrain more efficient and compatible with both Shimano 11- and 12-speed freehubs. The revolutionary off-road shifting system of the HYPERGLIDE+ cassettes delivers seamless shifting throughout the entire range. Even under maximum effort, you don't have to throttle down to shift. With the Shimano ULTEGRA R8150 drivetrain, you achieve maximum efficiency in every gear. The ULTEGRA CS-R8100 cassette now offers 12 gears and is the new benchmark for road shifting. Product specifications - Model: CS-R8100-12 - Series: ULTEGRA R8100 Series - Average weight: 291 (11-30T) 345 (11-34T) - Combination: 11-12-13-14-15-16-17-19-21-24-27-30T | 11-12-13-14-15-17-19-21-24-27-30-34T - Combination name (group name): 11-30T 11-34T - Type: HYPERGLIDE + - Compatible chain: HG 12-speed - Rear gears: 12 - Aluminum chainring_Qty.(pcs): 0 - Aluminum spider arm_Qty.(pcs): 2 - Spline type_HG spline L2 (ROAD 12-speed dedicated): Yes - Steel chainring_Qty.(pcs): 12 - Titanium chainring_Qty.(pcs): 0