Each belt disk consists of three elements:
Adapter plate. It connects hub and belt. On the inner side, it has either five holes on a bolt circle 74mm or a contour for Shimano 9-spline hubs, 3-fold contour of most internal hubs and others, on the outer side the shape of the belt geometry.
Thickness of the adapter plate is 3mm.
Belt disk. Two of these disks are screwed either to the left or right side of the adapter or to both sides.
This allows to get nearly any chainline by simply switching a disk from one into another position.
If you plan to use the belt drive on a bike with higher power output (tandem, electic engine) please use one or two additional toothed disks. We send you the corresponding belt (8 or even 10mm wide).
On the inner and outer side there are two protection disks, that hold the whole package together.