GP - Cervelo 4 pawl cassette.
From 2016 HED hubs used on the GP wheels and Cervelo bikes used a 15mm axle 4 pawl hub. This replacement cassette body is available only in Shimano and Sram fitting.
This is the new 4 Pawl model and will only work with the 4 pawl hubs.
The Shimano - Sram version, comes with the correct spaces to run 10-speed Shimano or Sram.