Aircraft & Status

Adult Helmet Sizing	Size (cm)	Size (in)	Liner Size
XS	53 - 54	20 7/8 - 21 1/4	14mm
S	55 - 56	21 5/8 - 22	12mm
M	57 - 58	22 1/2 - 22 7/8	12mm
L	59 - 60	23 1/4 - 23 5/8	14mm
XL	61 - 62	24 - 24 3/8	14mm
XXL		24 3/4 - 25 1/4

Trajecta

Adult Helmet Sizing	Size (cm)	Size (in)
S	52 - 56	20 1/2 - 22
M	56 - 58	22 - 22 7/8
L	58 - 61	22 7/8 - 24
XL	61 - 64	24 - 25 1/4

Altec

Adult Helmet Sizing	Size (cm)	Size (in)
XS/S	50 - 55	19 5/8 - 21 5/8
S/M	55 - 59	21 5/8 - 23 1/4
L/XL	59 - 63	23 1/4 - 24 3/4

 

Youth Helmets Sizing	Size (cm)
S	47- 48
M	49- 50
L	51 - 52