Ring sizer tool

This could be used for drawing but it is intended to be a ring sizer. It has sizes 5 to 13.

Demnsions:

5: 15.6mm
5.5: 16.0mm
6: 16.45mm
6.5: 16.9mm
7: 17.3mm
7.5: 17.7mm
8: 18.2mm
8.5: 18.6mm
9: 19.0mm
9.5: 19.4mm
10: 19.8mm
10.5: 20.2mm
11: 20.6mm
11.5: 21.0mm
12: 21.4mm
12.5: 21.8mm
13: 22.2mm