The Petzl Picchu Climbing/Cycling helmet meets European and U.S. standards for climbing and biking so your little adventurer can enjoy the outdoors. Helmet is specifically sized for children between 3 and 8 years with a head circumference of 48 - 54cm 18.9 - 21.3 in.. Expanded polystyrene liner absorbs impacts injection molded ABS plastic shell is lightweight and durable. Interior headband adjusts for a secure, comfortable fit chin strap position adjusts forward and back and the side-release buckle is positioned off to the side for comfort. Side openings promote ventilation interior foam padding is removable and washable. Included Petzl Signal light clips on the rear mount to increase visibility at night. Includes a page of reflective stickers so your child can personalize the helmet. 4 clips let you attach a headlamp sold separately. Helmet is not compatible with the Petzl Vizion face shield.