Shimano XT M8100 12 Speed Cassette - 10-45TShimano XT M8100 12 Speed Cassette 10 45T 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 construction Reduces cassette inertia resulting in faster acceleration and increased chain security 10T lowest sprocket realized by new FREEHUB body