Bern 2016 Women's Melrose Summer Bike Helmet w/Visor Head Size: 52-55.5 cm Constructed with liquid injected Zipmold Foam Complies with CPSC, ASTM F 2040 & EN1078 safety standards 16 vents for max air flow. Adjustabile BOA dial gives you maximum range of fit. Cold weather liners available but not included