| Diametro in mm. | Misure italiane | USA & Canada | UK |
| 14.0 | 4 | 3 | F |
| 14.3 | 5 | ||
| 14.6 | 6 | 4 | H |
| 15.0 | 7 | I | |
| 15.3 | 8 | 4,5 | I - ½ |
| 15.6 | 9 | J | |
| 15.9 | 10 | 5 | K |
| 16.2 | 11 | L - ½ | |
| 16.5 | 12 | 6 | |
| 16.8 | 13 | 6,5 | N |
| 17.2 | 14 | O | |
| 17.5 | 15 | 7 | |
| 17.8 | 16 | P | |
| 18.1 | 17 | 8 | Q |
| 18.4 | 18 | 8,5 | |
| 18.8 | 19 | R | |
| 19.1 | 20 | 9 | S |
| 19.4 | 21 | ||
| 19.7 | 22 | 10 | T |
| 20.0 | 23 | U | |
| 20.3 | 24 | 10,5 | V |
| 20.6 | 25 | 11 | W |
| 21.0 | 26 | X | |
| 21.3 | 27 | 12 | Y |
| 21.6 | 28 | Z | |
| 22.0 | 29 | ||
| 22.3 | 30 | 13 | 1 |