High performance 9-speed cassette Hyper glide 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 Two largest sprockets are mounted on a lightweight alloy carrier to reduce weight and increase rigidity Sprockets are cut away and drilled to further reduce weight without reducing rigidity Chrome-plated finish offers hard wearing resistance to corrosion Chrome-plated steel cassette locking For Super Narrow 9-speed HG chains Weight: 203 grams for 11 - 23T