Stan's 1.8mm Cassette Spacer Description: This 1.8mm Cassette Spacer is perfect for using a SRAM XD cassette on a SRAM XDR freehub body. It also is the right size for using an 8-10 speed Shimano HG-style cassette on a 11/12 Speed HG road freehub body. Features: 1.8mm cassette spacer allows for broader cassette compatibility Adapts SRAM XDR freehub for use with an XD cassette Adapts 11/12 Speed HG freehub for use with 8, 9, and 10 speed cassettes (and 11 speed mountain/Dynasys)