Shimano HG70-I 8 Speed Cassette: High quality 8-speed cassette IG sprockets have a computer designed tooth configuration with contoured shift gates, resulting in a crisp smooth up-shifts & down-shifts. The close ratio gearing allows a more efficient use of energy through finer cadence control. Sprockets are cut away to further reduce weight without reducing rigidity Pearl-bright finish offers hard wearing resistance to corrosion Pearl-bright steel cassette lockring For Narrow 8-speed IG chains