Saris Freehub XD/XDR
This freehub body from Saris is a genuine replacement part that enables you to use SRAM 11 and 12-Speed XD and XDR cassettes with the Hammer, H2 and H3 direct-drive smart trainers.
SRAM XD compatible with cassette adapter included
SRAM XDR compatible without spacer
Works with Hammer, H2 and H3 trainers