Drivetrains are constantly evolving. It can be tough to keep up with the options, and expensive to try to stay on top. The good folks at Easton feel your pain, and they know that you love your Easton wheels. That's why they made the Easton XD Driver so you can keep your Eastons and keep up with the XX1 Joneses.Unfortunately, SRAM's 11 speed XX1 group requires a totally different freehub body than the standard 9 or 10 speed SRAM or Shimano freehub body. The XD Driver solves this problem. It's compatible with Easton's M1 121, M1 221, M1 321, and M1 322 hubs, so your late model Easton wheels are probably covered. However, you'll want to check the part number printed on your hub before ordering.