GMax Helmets - Size Chart
Helmet Size	Head Cir. (IN)	Head Cir. (CM)	Hat Size
Youth S/M	19-11/16 - 20-1/16	50 - 51	6-1/4 - 6-3/8
Youth L/XL	20-7/16 - 20-7/8	52 - 53	6-1/2 - 6-5/8
XS	21-1/4 - 21-5/8	54 - 55	6-3/4 - 6-7/8
S	22 - 22-7/16	56 - 57	7 - 7-1/8
M	22-13/16 - 23-1/4	58 - 59	7-1/4 - 7-3/8
L	23-5/8 - 24	60 - 61	7-1/2 - 7-5/8
XL	24-3/8 - 24-13/16	62 - 63	7-3/4 - 7-7/8
XXL	25-3/16 - 25-5/8	64 - 65	8 - 8-1/8
XXXL	26 - 26-3/8	66 - 67	8-1/4 - 8-3/8