Typhoon Helmets Adult Snowmobile Helmet with Electric Heated Shield Mens Womens Full Face Dual Lens - Blue (XXXL) Heated electric shield w/ cord included! Certified to meet the DOT standard (FMVSS 218) Opening & closing twin top and lower air intakes allow for adjustable air flow Adjustable breathbox & chin skirt included Please measure for size. Each manufacturers sizing is different. SIZE CHART (Circumference of the largest part of your head, usually just above the eyebrows) in inches. SMALL: 21 to 21  - MEDIUM: 21  to 22 - LARGE: 22 to 22  - XL: 22  to 23 - XXL: 23 to 23  - XXXL: 23  to 24. Head shapes can affect how a helmet fits. The size chart is meant to be a starting point. High-density EPS energy absorbing inner shell Fully removable &amp; washable comfort liner made of soft &amp; durable material Twin top air intakes Single Lower lens intake Open &amp; close chin bar venting system Adjustable breath box included &amp; chin skirt(as shown in last sample picture) Dual Lens face shield with anti-fog coated inner lens &amp; hard coated outer lens for scratch resistance Multi-positional ratchet system Meets DOT Standards Fabric Helmet Bag included Take a head measurement with a cloth tape measure. Wrap the tape measure around your head one inch above your eyebrows, directly above your ears and to the widest area at the back of your head. This will give you the circumference, which is the measurement displayed below.