The Shimano ULTEGRA 12-speed HYPERGLIDE+ road cassette is designed for smooth shifting and optimal efficiency while riding on the road. With its refined 12-step cogset, this cassette offers maximum acceleration performance in any racing situation. Shifting is fast and smooth, even under maximum pedaling force. This cassette is suitable for both 12-speed and 11-speed road freehubs. The ULTEGRA CS-R8100-12 cassette has an average weight of 291 grams (11-30T) or 345 grams (11-34T) 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