| US Size | Japan Size | UK Size | EU Size* | Inner Diameter (mm) |
Inner Circumference (mm) |
|---|---|---|---|---|---|
| 3.0 | 4 | F | 44 | 14.1 | 44.3 |
| 3.5 | 6 | G | 46 | 14.5 | 45.6 |
| 4.0 | 7 | H | 47 | 14.9 | 46.8 |
| 4.5 | 8 | I | 48 | 15.3 | 48.1 |
| 5.0 | 9 | J | 49 | 15.7 | 49.3 |
| 5.5 | 11 | K | 51 | 16.1 | 50.6 |
| 6.0 | 12 | L | 52 | 16.5 | 51.8 |
| 6.5 | 13 | M | 53 | 16.9 | 53.1 |
| 7.0 | 14 | N | 54 | 17.3 | 54.3 |
| 7.5 | 16 | O | 56 | 17.7 | 55.6 |
| 8.0 | 17 | P | 57 | 18.1 | 56.9 |
| 8.5 | 18 | Q | 58 | 18.5 | 58.1 |
| 9.0 | 19 | R | 59 | 18.9 | 59.4 |
| 9.5 | 21 | S | 61 | 19.4 | 60.9 |
| 10.0 | 22 | T | 62 | 19.8 | 62.2 |
| 10.5 | 23 | U | 63 | 20.2 | 63.5 |
| 11.0 | 25 | V | 65 | 20.6 | 64.7 |