OUTER SHELL: ABS Plastic. INNER SHELL: HD Polystyrene. HEADBAND: PE Polythene. SIZE UNIVERSAL: Adjustable 51-62cm. WEIGHT: 450g/0.99 lb (visor and ear muffs are not included). STANDARD: Type I, Class C helmet based on ANSI Z89.1-2009 classification. / CSA 89.1-2009 (USA & Canada). LAMP CARRYING SYSTEM - External Nylon 6.6 Lamp Clips. ADJUSTMENT SYSTEM: Up & Down