Womail 10 Vent Child Sports Mountain Road Bicycle Bike Cycling safety Helmet Pink Head Circumference:45-56cm Fashion design:Specifically 10 wind hole design,unique Durable material: high quality plastic and high density EPS Duct design:Wind tunnel, effectively reduce wind resistance Comfortable to wear:Well-ventilated and comfortable,a labyrinth of optimized internal channels allow the bike helmet to breathe like no other,you might even forget that you're wearing anything at all.