Size chart
| WILLIAM FAN | IT | FR | UK | US | JP | CN |
| XXS | 36 | XXS | 4 | 00 | 3 | 150/72A |
| XS | 38 | XS | 6 | 0 | 5 | 155/76A |
| S | 40 | S | 8 | 2-4 | 7 | 155/80A |
| M | 42 | M | 10 | 4-6 | 9 | 160/84A |
| L | 44 | L | 12 | 8 | 11 | 165/88A |
| XL | 46 | XL | 14 | 10 | 13 | 170/92A |
| XXL | 48 | XXL | 16 | 12 | 15 | 175/96A |
| WILLIAM FAN | IT | FR | UK | US | JP | CN |
| XXS | 36 | XXS | 4 | 00 | 3 | 150/72A |
| XS | 38 | XS | 6 | 0 | 5 | 155/76A |
| S | 40 | S | 8 | 2-4 | 7 | 155/80A |
| M | 42 | M | 10 | 4-6 | 9 | 160/84A |
| L | 44 | L | 12 | 8 | 11 | 165/88A |
| XL | 46 | XL | 14 | 10 | 13 | 170/92A |
| XXL | 48 | XXL | 16 | 12 | 15 | 175/96A |