Happyjoy Cycle Bike Helmet and Skate Helmet Vented Design Lightweight 55 - 58cm Head Circumference Unisex Kids Boys Girls Material: PC shell(more durable than PVC), EPS inner shell-Shock absorbing EPS inner liner for added protection Fits most kids (55 - 58cm/ 21.5 - 22.5" Head Circumference). Note: Please make sure the size could fit before ordering, check the seventh photo to get help. Vented design - 11 air vents for maximum comfort. Easy to adjust chin straps for a safer comfy fit Lightweight design, weighs only 240g Meets CE and EN1078 Certification