The tool has an internal anticlastic curve which when closed will go to a size J and a width of 12mm when fully closed.
If you are making a wider ring, close it less and you’ll get a wider band. The curves will extend out to size 34mm so about Size Z+20.
The bigger the band the less anticlastic effect you’ll get as standard from the squish effect, but you can follow up with a shaped delrin/nylon or steel hammer to chase the curves in.
A full instructions sheet is provided with the tool.
There are 2 mandrel sizes available, regular and small. The regular size suits spinner rings that have a 10mm or wider band. The small version is more suitable for thinner bands of less than 10mm.