HRP Ring Size Table
| HRP Size | X Small | Small | Medium | Large | X Large | XX Large |
| Internal Diameter (mm) | 16.00 | 16.4 | 16.79 | 17.18 | 18.58 | 18.76 |
| Internal Circumference (mm) | 50.27 | 51.30 | 52.56 | 54.00 | 55.00 | 59.00 |
| British UK | K | L | M | N | O | R |
| Europe | 10.27 | 11.30 | 12.56 | 14.00 | 15 | 19.00 |
| Japan | 10 | 11 | 12 | 14 | 15 | 18 |
| USA | 5.5 | 6 | 6.25 | 7 | 7.25 | 8.75 |