Helmet sizing

XS - Under 21 5/8"
SM - 21 5/8" TO 22"
MED - 22 3/8" TO 22 3/4"
LG - 23 1/8" TO 23 1/2"
XL - 23 1/2" TO 23 3/4"
XXL - Larger than 23 3/4"