Industry Nine Hydra & 1/1 drive side end caps for Industry Nine hubs. Shimano Microspline requires a different end cap than the Shimano HG / SRAM XD freehubs. When converting to or from Microspline, you will need a new drive-side end cap. Details: Rear: Fits 12 x 142mm, 12 x 148mm, 12 x 157mm, 12 x 177mm or 12 x 197mm hubs For 1/1 and Hydra hubs, drive-side only Compatible with both 6-bolt and centerlock 1/1 hubs.