| Head Circumference (cm) | 47 - 51 cm | 51 - 55 cm | 55 - 59 cm | 59 - 62 cm |
| Head Circumference (in) | 18.5 - 20 | 20 - 21 5/8 | 21 5/8 - 23 1/4 | 23 1/4 - 24 3/8 |
| Hat Size | 6 - 6 3/8 | 6 3/8 - 6 7/8 | 6 7/8 - 7 3/8 | 7 3/8 - 7 3/4 |
| Pret Helmet Size | XS | S | M | L |
| Head Circumference (cm) | 49 - 54 cm | 54 - 58 cm |
| Head Circumference (in) | 19 - 21 | 21 - 23 |
| Pret Helmet Size | XS/S | S/M |