Industry Nine Hydra 2 Classic Rear Hub - 12 x 148mm 6-Bolt Micro Spline Blue 28HCompletely re engineered using insights gleaned from more than 100000 original Hydra hubs in the field Hydra 2 features a newly designed 65% thicker axle larger 6903 bearings with new labyrinth seals and enlarged pawl pockets that ensure bombproof durability under the most demanding conditions. 6 Pawl Hydra 2 Freehub Body provides a groundbreaking 870 P. O. E. Hydra 2 Freehub body engages every . 41 degrees yielding telepathic control Refined drive