Sizing
| UK | US | EU | Inside circumference (mm) | Inside diameter (mm) |
|---|---|---|---|---|
| D | 2 | 42 | 41.70 | 13.27 |
| D½ | 2.25 | 42.5 | 42.30 | 13.46 |
| E | 2.5 | 43 | 42.90 | 13.66 |
| E½ | 2.75 | 43.5 | 43.55 | 13.86 |
| F | 3 | 44 | 44.20 | 14.07 |
| F½ | 3.25 | 44.5 | 44.85 | 14.28 |
| G | 3.5 | 45 | 45.50 | 14.48 |
| G½ | 3.75 | 46 | 46.15 | 14.69 |
| H | 4 | 47 | 46.80 | 14.90 |
| H½ | 4.25 | 47.5 | 47.75 | 15.20 |
| I | 4.5 | 48 | 48.70 | 15.49 |
| I½ | 4.75 | 48.5 | 49.35 | 15.72 |
| J | 5 | 49 | 50.00 | 15.92 |
| J½ | 5.25 | 49.5 | 50.60 | 16.10 |
| K | 5.5 | 50 | 51.20 | 16.30 |
| K½ | 5.75 | 50.5 | 51.85 | 16.51 |
| L | 6 | 51 | 52.50 | 16.72 |
| L½ | 6.25 | 51.5 | 53.15 | 16.93 |
| M | 6.5 | 52 | 53.80 | 17.13 |
| M½ | 6.75 | 53 | 54.45 | 17.33 |
| N | 7 | 54 | 55.10 | 17.55 |
| N½ | 7.25 | 54.5 | 55.70 | 17.73 |
| O | 7.5 | 55 | 56.30 | 17.92 |
| O½ | 7.75 | 55.5 | 56.80 | 18.08 |
| P | 8 | 56 | 56.30 | 17.92 |
| P½ | 8.25 | 57 | 56.95 | 18.13 |
| Q | 8.5 | 58 | 57.60 | 18.33 |
| Q½ | 8.75 | 58.5 | 58.25 | 18.54 |
| R | 9 | 59 | 58.90 | 18.75 |
| R½ | 9.25 | 59.5 | 59.55 | 18.96 |
| S | 9.5 | 60 | 60.20 | 19.16 |
| S½ | 9.75 | 60.5 | 60.80 | 19.35 |
| T | 10 | 61 | 61.40 | 19.55 |
| T½ | 10.25 | 62 | 62.05 | 19.75 |
| 10.5 | 63 | 62.70 | 19.96 | |
| U½ | 10.75 | 63.5 | 63.35 | 20.16 |
| V | 11 | 64 | 64.00 | 20.38 |
| V½ | 11.25 | 64.5 | 64.65 | 20.58 |
| W | 11.5 | 65 | 65.30 | 20.79 |
| W½ | 11.75 | 66 | 65.95 | 20.99 |
| X | 12 | 67 | 66.60 | 21.20 |
| X½ | 12.25 | 67.5 | 67.20 | 21.39 |
| Y | 12.5 | 68 | 67.80 | 21.58 |
| Y½ | 12.75 | 68.5 | 68.15 | 21.69 |
| Z | 13 | 69 | 68.50 | 21.80 |
| Z½ | 13.25 | 69.5 | 69.25 | 22.04 |
| Z1 | 13.5 | 70 | 70.00 | 22.28 |