The Shimano XTR M9000 11 Speed Cassette has 11-40T wide ratio gearing allows a more efficient use of energy through finer cadence control. It has four separate Carbon Fibre carriers & 6 titanium sprockets, the carbon fibre carriers reduce weight & increase stiffness giving more precise & faster shifting. The 6 titanium sprockets help make this Shimano's lightest 11-speed Dyna-Sys MTB cassette. The Hyperglide sprockets have a computer designed tooth configuration with contoured shift gates, resulting in a crisp smooth shift even under load. The Sprockets are cut away extensively & drilled to further reduce weight without reducing rigidity & Nickel-plated finish offers hard wearing resistance to corrosion. Designed for use with 11-speed SIL-TEC chains.