Place the string or tape around your head just above your ear all around your head across the mid-forehead, without holding the tape too tightly.
O/S = One Size
| KN | O/S | |||||||
| Centimetres | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 |
| Size | S | S/M | M | M/L | L | L/XL | XL | XL |
| UK Size | 63⁄4 | 67⁄8 | 7 | 71⁄8 | 71⁄4 | 73⁄8 | 71⁄2 | 75⁄8 |
| US Size | 67⁄8 | 7 | 71⁄8 | 71⁄4 | 73⁄8 | 71⁄2 | 75⁄8 | 73⁄4 |
| Inches | 21,7 | 22 | 22,4 | 22,8 | 23,2 | 23,6 | 24 | 24,4 |