OTK sprocket hub made of aluminium (30mm) or magnesium. (40&50mm). Available in sizes to suit 30mm axle, 40mm axle and 50mm axle all with 8mm keyway. It has a 6 bolt pattern with 66mm spacing for attaching the sprocket and 1 pinch bolt to the axle for 30&40mm, 2 pinch bolts for 50mm.
