XT CS-M8100 Cassette - 12-SpeedDescription The Shimano Deore XT CS M8100 12 speed cassette is optimized with rider tuned wide range and close step gear combinations for MTB excellence. Features Shift ramp designs provide fast and smooth shifts by HYPERGLIDE+ technology Light and stiff construction reduces cassette inertia resulting in faster acceleration and increased chain security Designed with a Shimano Micro Spline body that features smaller and more widely distributed splines