Uses 6mm shaft rocker rings. Includes shafts, rocker rings, and bearing spacers. Height can be adjusted by changing the hole positions, and while I used them for wizard skating, I think they're also perfect for cruising. There are quite a few scratches, but the frame is not warped. The structure allows you to remove the shaft with a single hex wrench, which is surprisingly convenient. (Set the hexagonal rocker ring in the hexagonal hole on the shaft base and the circular hole rocker ring on the opposite side.) The last photo is an image of the setup. Thank you for looking.