This hub is designed to extend the compatibility of your Smart ZDrive direct drive roller. The device is a standard XD hub, which means that it is ready to accept any SRAM XD/R 11-speed or 12-speed cassette, such as the Eagle 12-speed cassette. Thanks to this modern hub, the compatibility with all types of bikes, especially Gravel and Cyclocross bikes, is considerably extended, as well as making road bikes more efficient when using the roller.