Adult Helmets
| Size | Head Circumference (cm) | |
| Regular Fit | Round Contour / Asian Fit | |
| Small | 51 - 55 | 55 - 59 |
| Medium | 55 - 59 | 59 - 63 |
| Large | 59 - 63 | 63 - 67 |
| X Large | 63 - 67 | N/A |
Holt & Junior Helmets
| Size | Head Circumference (cm) |
| Youth Small | 48 - 53 |
| Youth Medium | 53 - 58 |
| Youth S/M | 48 - 56 |
| X Small | 52 - 54 |
| Small | 54 - 56 |
| Medium | 56 - 58 |
| Large | 58 - 60 |
| X Large | 60 - 62 |