Inner diameter 17 mm - scale up/down (X+Y) for other dimensions. E.g. for 18 mm = 105,88 %, etc:
13 mm | 76,47% |
14 mm | 82,35% |
15 mm | 88,24% |
16 mm | 94,12% |
17 mm | 100,00% |
18 mm | 105,88% |
19 mm | 111,76% |
20 mm | 117,65% |
21 mm | 123,53% |
22 mm | 129,41% |
23 mm | 135,29% |
24 mm | 141,18% |
The author hasn't provided the model origin yet.