Pro-Tec's Classic Certified Helmet features their most durable, high impact absorbing ABS shell that's lined with high impact absorbing EPS foam both designed to work together to stop a slam from taking you out. Eleven open vents across the helmet provide plenty of ventilation to get cool air in and let hot air escape, with compression moulded padding on the interior keeping the fit of the helmet comfortable. Nylon webbing strap with buckle can be easily and quickly adjusted to get a secure fit. Certification: CE EN 1078 European Saftey Standard. Sizing: XX-Small: 49 - 51cm X-Small: 52 - 54cm Small: 54 - 56cm Medium: 56 - 58cm Large: 58 - 60cm X-Large: 60 - 62cm XX-Large: 62 - 64cm