Use a metric tape to measure the contour of the head for the area indicated in the image (cranial perimeter) without making too much pressure. The measure in centimeters will indicate you the corresponding size according to the following chart:
SIZE*
Inches
Centimeters
XS
20.87/21.26
53/54
S
21.65/22.05
55/56
M
22.44/22.83
57/58
L
23.23/23.62
59/60
XL
24.02/24.41
61/62
XXL
24.80
63
*These sizes are not available in all helmets.
One Fits All
We suggest this solution only for those pilots who fly with different passengers with different sizes. You can change the size very quickly and also very easily the transpirant paddings. Please note that the interchangeable internal padding is more confortable.
By Internal Padding
For the HORUS helmet model, the helmet size is determined by the size of the internal padding placed. This way you can change size without changing the helmet, just ordering a new size of internal padding.