The Shimano Dura-Ace CS-6800 Cassette, with 11 speeds! Now, you get more usable gears in each cassette range. When paired with Shimano HYPERGLIDE (HG) chains, HG cassette sprockets deliver a fast and precise index shifting action. The computer-designed sprockets incorporate specifically positioned shift ramps and tooth profiles for improved chain control during shifting. Responsive, smooth and low-noise shifting is the result.