Bern 2016 Women's Prescott Summer Bike Helmet w/Visor Head Size: 52-55.5 cm Zipmold liquid foam technology offers a thinner profile than the standard EPS grey foam other brands use, giving you a much smaller helmet shape. BOA dial on back of helmet quickly secures or loosens the fit around your head, super easy to adjust - even on the fly. Meets Safety Certification ASTM F 2040, CPSC and EN 1078 and WINTER UPGRADE KIT AVAILABLE SEPARATELY