The Classic Certified Helmet features Pro-Tec\'s most durable outer high impact absorbing ABS shell, 11 open vents and an EPS foam liner with compression moulded padding. Shell: Durable and tough, Injection moulded ABS (acrylonitrile butadiene styrene). Liner: High impact absorbing EPS foam (expanded polystyrene). Vents: 11 open holes for ventilation. Interior: Compression moulded padding. Nylon webbing strap with buckle. Certification: CE EN 1078 European Saftey Standard. SIZING: XXXS - 47-49cm XXS - 49-51cm XS - 52-54cm S - 54-56cm M - 56-58cm L - 58-60cm XL - 60-62cm XXL - 62-64cm