| Small | Medium | Large | |
| Circumference |
21.5 | 22.5 | 23 |
| Front of head to nape |
13.6 | 14.5 | 15.5 |
| Ear to Ear across hairline |
10.8 | 11.5 | 12 |
| Ear to Ear over top of head |
12.5 | 13 | 14 |
| Temple to Temple |
14.5 | 15.5 | 16.7 |
| Nape of Neck |
4.8 | 5.0 | 5.8 |