Easton Freehub Body SRAM XX1"XD Driver" Cassette body for SRAM XX1 cassettes for Easton M1-121, M1-221, M1-321, and M1-322 hubs.If you want to run SRAM's 12-speed drivetrains on your bike, you need to switch to a XD freehub. The freehub comes with the pawls and springs installed making replacement quick and easy.SpecificationsEaston XD 11 Speed Freehub Driver - Easton XD Driver for SRAM 11-12 Speed | Easton XD 11 Speed Freehub Driver Easton XD Driver for SRAM 11 Speed