Shimano sora hg50 8 speed road cassettehg sprocket design computer designed hg hyperglide sprockets insure fast and quiet down shifts as well as instant up shifts without hesitation features high quality 8 speed road cassette hyperglide sprockets have a computer designed tooth configuration with contoured shift gates resulting in a crisp smooth shift even under loadclose ratio gearing allows a more efficient use of energy through finer cadence controlsprockets are cut away to further reduce