Smith Optics Overtake Bike Adult Cycling Helmet AEROCORE construction uses materials such as Koroyd & EPS to keep the helmet light while being as shock absorbent as possible 21 optimized vents keep you cool without sacrificing aerodynamics VaporFit Adjustable System allows for optimum fit with ease Works with Smith Optics eyewear as a system- sunglasses & goggles fit perfectly Certifications: Safety Standard for Bicycle Helmets (16 CFR Part 1203)