The uninterrupted shifting experience of the ULTEGRA R8100 12-speed cassette range lets you climb, sprint, or cruise without stopping to think about your next gear change. Larger driving cogs maximize drivetrain efficiency and create compatibility with both Shimano 11 and 12-speed FREEHUB bodies. HYPERGLIDE+ cassettes revolutionized off-road shifting with its seamless shifts both up and down the gear range. Now it's time for the technology to change road cycling. Even during maximal efforts up a climb or racing a friend, riders no longer need to back off to perform a shift. In any gear, Shimano ULTEGRA R8150 drivetrains maximize efficiency thanks to larger cogs and retain compatibility with existing HYPERGLIDE FREEHUB bodies. All this while increasing to 12-gears, ULTEGRA CS-R8100 cassettes are the new paradigm in road shifting. Feature: 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 and road 11-speed FREEHUB body SKU: CS-R8100