The Shimano CS-M9001 XTR 11 Speed Cassette has four Carbon Fibre carriers and 6 titanium sprockets, which 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. Shimano CS-M9001 XTR 11 Speed Cassette Features 11-40T wide ratio gearing allows a more efficient use of energy through finer cadence control Four separate lightweight carbon fibre carriers reduce weight and increase stiffness giving more precise faster shifts 35/31/27/24/21/19T sprockets are all made from Titanium to reduce weight and increase durability Sprockets are cut away extensively and drilled to further reduce weight without reducing rigidity Nickel-plated finish offers hard wearing resistance to corrosion Alloy cassette lockring For use with 11-speed SIL-TEC chains