The CS-M6100 cassette features Hyperglide+ technology that ensures secure and quick shifts both when "upshifting" gears and when the chain follows a reverse path. Designed for a Micro Spline freewheel system with 22 teeth spaced equally, it covers a wide range of gears (from 10 to 51 teeth). Manufactured with materials that ensure weight reduction without losing any of the sturdiness and strength you expect from a cassette of this level.