The Shimano Dura-Ace CS-7900 Bicycle Cassette - 10 Speed features hyperglide sprockets which have a computer designed tooth configuration with contoured shift gates, allowing for smooth shifting even under a heavy load. With close ratio gearing for more efficient energy use through improved cadence control, the largest sprockets are mounted onto a lightweight alloy carrier to enhance rigidity and reduce weight. - L.M. Features: Shimano Dura-Ace CS-7900 Bicycle Cassette - 10 Speed Computer designed tooth configuration with contoured shift gates Allow for smooth shifting, even when under a heavy load Close ratio gearing for more efficient energy use through improved cadence control Largest sprockets are mounted onto a lightweight alloy carrier to enhance rigidity and reduce weight Nickel-plated finish offers hard wearing resistance to corrosion Includes alloy cassette lock ring. For Super Narrow 10-speed HG chains Weight: 163g Please Note: CS-7900 11-27 and 11-28 cassettes require the use of RD-7900 or RD-6700 (rear derailleur)