| Size | Head Circumference (cm) | Head Circumference (inches) |
| S | 54 - 56 cm | 21.2" - 22.0" |
| M | 56 - 58 cm | 22.0" - 22.8" |
| L | 58 - 60 cm | 22.8" - 23.6" |
| XL | 60 -62 cm | 23.6" - 24.9" |
RAD Skate Helm Size chart
| Size | Head Circumference (cm) | Head Circumference (inches) |
| S | 54 - 56 cm | 21.2" - 22.0" |
| M | 56 - 58 cm | 22.0" - 22.8" |
| L | 58 - 60 cm | 22.8" - 23.6" |
| XL | 60 -62 cm | 23.6" - 24.9" |