Giro Omen 2009 Snow Helmet Available in 3 In Form Sizes: S(52-55.5cm), M(55.5-59cm), L (59-62.5cm) In-Mold construction with high-impact ABS zones and X-Static anti microbial padding 14 Wind Tunnel vents with Dual Thermostat control Compatible with all after market TuneUps systems Compliance: ASTM F2040/CE EN1077