Shimano XT CS-M8100 Cassette The new generation of XTShowcasing Shimano's new revolutionary HYPERGLIDE+ technology, the new 12-speed XT CS-M8100 Cassette provides improved shifting efficiency up and down the cassette. Paired with the new Shimano MICROSPLINE freehub, you have an incredibly lightweight package that delivers industry leading performance. The high geared 10-speed cog gives you all the speed you need to sprint to the finsih, and either a 51T or 45T low gear allows you to effortless ascend the steepest trails. The 51T cassette pairs with a single ring up front while the 45T cassette is compatible with a single or double chainring up front. Features Wide range and close step 12-speed drivetrain Hyperglide+ Technology Compatible with Microspline freehub Range options: 10-45T, 10-51TShimano Part Number: CS-M8100SPECIFICATIONSSpeeds12Gear Range10-45T10-51TFreehub compatibility Microspline Material Aluminum (45-51) & Steel (10-12-14-16-18-21-24-28-33-39)Weight461g (10-45 T) , 470g (10-51 T) | Shimano | Xt Cs-M8100 12 Speed Cassette 10-51 Tooth