There are no modules on the ZXT bow and most of Mathews other single cam bows, it is a draw length specific cam. The ZXT and Z7 Extreme cams are interchangeable, the only difference is the red side of the cam from the Z7Extreme v. black on the ZXT model. This other part looks like a module, but the “roll-over” part of the cam is different from draw length to draw length as well. Shoot straight!!