The new XT M8100 12-Speed Cassette from Shimano features their fantastic Hyperglide+ technology and new shift ramp design to provide the smoothest shifts possible.New shift ramp designs provide the fastest, smoothest shifts by HYPERGLIDE+Lighter and stiffer constructionReduces cassette inertia resulting in faster acceleration and increased chain security10T lowest sprocket realized by new FREEHUB body constructionHyperglide+ technology will help kickstart the next generation of mountain bike riding by introducing continuous pedalling over virtually any terrain. This revamped drive system and dedicated chain deliver fast shifting, efficient power transfer and chain stability like you ve never experienced before. This cassette has a lighter and stiffer sprocket construction that reduce inertia and increases acceleration.  Its supported by Shimano s new Freehub body which allows a 10T lowest sprocket and increase the gear range at your disposal.