Four carbon fibre carriers and 6 titanium sprockets make this shimano39s lightest 11 speed dyna sys mtb cassette hyperglide sprockets have a computer designed tooth configuration with contoured shift gates resulting in a crisp smooth shift even under load 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 35312724211