Shimano knew that the Ultegra 6800 cassette would reside as the heart of the new 11-speed system, which is why it devoted considerable time on a feature known as "rider-tuning." What this means is that you receive an updated range of useable gearing options with the advent of the 11-speed design. Cassette options with Ultegra 6800 now range from 11-23 to its climber-friendly 11-32. The additional cog in the back means the new cassette runs straight through for a bit longer, which generally means the addition of an 18T cog over the 10-speed. This smoother run of gearing is most noticeable while spinning in the top end of the block, allowing more consistency and control over your cadence compared to 10-speed cassettes. Shimano Ultegra CS-6800 Cassette is slightly lighter than its 6700 brother, and it does a nice job of closing the gap on Dura-Ace 9000. The tallest cogs are riveted onto an aluminum carrier for weight savings, and they"re gentler on aluminum cassette bodies. Shimano improved its manufacturing quality too; now they can make the ramps stronger because they can build to tighter tolerances. And the ramps themselves have been revised for faster shifting. The Ultegra CS-6800 Cassette has 11 cogs and comes in the following ratios: 11-23T, 11-25T, 12-25T, 11-28T, and 11-32T. Each cassette wears a nice chrome finish and comes with an alloy lock ring. Please note that the CS-6800 is recommended to be paired with corresponding Ultegra 6800 components.