Sizing Chart M | 22.4 - 22.8 in | 57 - 58 cm L | 23.2 - 23.6 in | 59 - 60 cm XL | 24.0 - 24.4 in | 61 - 62 cm Advanced ABS shell with high pressure thermoplastic technology. Extremely durable composite shell,Beautiful glossy UV protective finished , DD-Ring Fastening Heavily cushioned and very comfortable interior; Removable and washable padding, adjustable circulation vents Fire retardant padded interior and airflow venting for comfort Motorcycle Helmet Meets or Exceeds FMVSS-218 and DOT Safety Standards