AUBBC Cycling Bike Sports Safety Bicycle Adult Men Helmet (Black Green 56-62CM) 1.Ventilation with more than 20 hole,use air cooling make the air free 2.Certification: CE ,SGS,CPSC 3.Size: For head circumference (56-62cm) 4.Material: Outside:PC,inside:EPS,PU foam, adjust fish silk belt 5.Applicable : Cycling as well as other outdoor activities