Suomy Helmet Sizing Chart
Size	Centimeter	Inches	Hat Size
XSm	53-54	20 1/2 - 20 7/8	6 1/2 - 6 5/8
Sm	55-56	21 1/4 - 21 5/8	6 3/4 - 6 7/8
Md	57-58	22 - 22 1/2	7 - 7 1/8
Lg	59-60	22 7/8 - 23 1/4	7 1/4 - 7 3/8
XL	61-62	23 5/8 - 24	7 1/2 - 7 5/8
XXL	63-64	24 1/2 - 24 7/8	7 3/4 - 7 7/8
XXXL	65-66	25 1/4 - 25 5/8	8 - 8 1/8