The Shimano CS HG50 10 speed cassette is a high quality Dyna Sys 10 speed cassette. It features close ratio gearing which allows a more efficient use of energy through finer cadence control & sprockets are cut away & drilled to reduce weight without reducing rigidity. A nickel-plated finish offers hard wearing resistance to corrosion & comes with a corrosion-resistant steel cassette lock ring. Designed for use with 10-speed HG-X MTB chains.