Contoured drop back shell and comfort foam interior cradle the head for increased protection and functioning top and rear vents for high temperature relief. A helmet is only safe, if it fits correctly. It is always better to be fit by a professional than it is to purchase a helmet on line. Tipperary Size Helmet Size Head Circumference (in) X-Small 6 1/4 - 6 3/8 19 - 19½ Small 6 1/2 - 6 5/8 20 - 20½ Medium 6 3/4 - 6 7/8 21 - 21½ Large 7 - 7 1/8 22 - 22½ X-Large 7 1/4 - 7 3/8 23 - 23½ We're riders ourselves, so we understand that finding the right helmet is not always easy. We would be happy to help you, please call or email us with any questions; we are your friendly neighborhood tack shop online. Tipperary Sportage Helmet