OAKLEY ARO5 HELMETWhen every second counts in a race and you need an aerodynamic advantage, then you'll need an Oakley ARO5 Helmet. It has a lightweight polycarbonate shell that has an integrated eyewear dock so you can securely store your glasses when they're not in use, X-Static brow padding that helps wick moisture away and inhibits the growth of bacteria on the fabric, MIPS to help protect the brain from rotational motion transferred to the brain from angled impacts, and a Boa FS1-1 system that provides a 360deg fit system for ultimate comfort and fit.FeaturesBoa FS1-1 System provides an adjustable 360deg design that delivers exact fitMIPS helps protect the brain from rotational motion transferred to the brain from angled impactsLightweight polycarbonate shell with integrated eyewear dockSPECIFICATIONSShell MaterialPolycarbonateCore MaterialEPS FoamVents-Safety CertificationsCPSCIntended UseRoad RaceWeight300 GramsSizeSmallMediumLargeSize Range (in)6-1/2" - 7-1/8"6-3/4" - 7-3/8"7-1/8" - 7-5/8"Size Range (cm)52cm - 56cm54cm - 58cm56cm - 60cm | Oakley Aro5 Helmet Men's Size Medium/Large in Black