HG81 10-Speed Dyna-Sys cassette featuring light weight minimal design sprocket carrier The 3 largest sprockets are mounted on a lightweight alloy carrier to reduce weight and increase rigidity Hyperglide sprockets have a computer designed tooth configuration with contoured shift gates, resulting in a crisp smooth shift even under load Close ratio gearing allows a more efficient use of energy through finer cadence control Sprockets are cut away and drilled to reduce weight without reducing rigidity For 10-speed HG-X MTB chains Average weight: 351 g for 11 - 34T