The Blue M1 cassette body fits Easton M1 and X4 hubs and has Shimano HG-E splines for eleven speed Shimano/Sram road cassettes.

"XD Driver” Cassette body for SRAM XX1 cassettes for Easton M1-121, M1-221, M1-321, and M1-322 hubs.

Fits on M1-121, M1-221, and M1-321 hubs. Does not fit on M1-120 or M1-220, use the orange R4 body for these.