Measuring your head with a fabric tape measure around the circumference of your head holding the tape just above your eyebrows and ears. 1" = 25mm
| D3/D4 Helmet Size Chart | |||||||||||||||
|
Head Circumference |
Inches | 20 1/2 | 20 7/8 | 21 1/4 | 21 5/8 | 22 | 22 3/8 | 22 3/4 | 23 1/4 | 23 5/8 | 24 | 24 3/8 | 24 3/4 | 25 1/4 | 25 5/8 |
| Hat | 6 1/2 | 6 5/8 | 6 3/4 | 6 7/8 | 7 | 7 1/8 | 7 1/4 | 7 3/8 | 7 1/2 | 7 5/8 | 7 3/4 | 7 7/8 | 8 | 8 1/8 | |
| CM | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | |
| D3 | XS | S | M | L | XL | XXL | |||||||||
| D4 | XS | S | M | ||||||||||||
| L | XL | XXL | |||||||||||||