The base model is a size 10 and I went through and did test prints to get as close as I could to general ring sizes to make things easier for folks to print. You may need to adjust as you see fit for shrinkage and other things but as it stands, it is close enough for a base!

These types of rings are used for all manner of finger issues but is generally seen for hypermobility, EDS (Ehlers-Danlos syndrome), trigger finger, swan neck, etc. I have personally done them in resin, PLA, and PETG. You can generally fir two of these per finger.

Ring Size 4: 75%
Ring Size 4.5: 77%
Ring Size 5: 80%
Ring Size 5.5: 82%
Ring Size 6: 83.5%
Ring Size 6.5: 85%
Ring Size 7: 88%
Ring Size 7.5 : 89.5%
Ring Size 8 : 90%
Ring Size 8.5 : 95%
Ring Size 9: 96.5
Ring Size 9.5: 98%
Ring Size 10: 100%
Ring Size 10.5: 102%
Ring Size 11: 104%
Ring Size 11.5: 105.5%
Ring Size 12: 107%
Ring Size 12.5: 108%
Ring Size 13: 110%
Ring Size 13.5: 115%