Features KID'S BIKE HELMET: ASTM & CPSC CERTIFIED SAFETY Our multi-sport helmet is certified by ASTM (American Society for Testing and Materials) & CPSC (U.S. Consumer Product Safety Commission) for maximum safety. WELL-SHAPED, SNUG FIT & COMFORTABLE Enjoy a flexible dial-fit system of lightweight bike helmets for sports and outdoor activities. Safety and Comfort at the same time! EXTREMELY STRONG ABS SHELL & EPS CORE We value your child's safety as much as you do, and this bike helmet safety for kids will not let you down. We feature Hard ABS SHELL and EPS CORE for additional protection and great Comfort with extra padded edges. GREAT VENTILATION 14 separate air vents will keep you cool & comfortable for hours of fun riding. ADJUSTABLE STRAPS Head Circumference 18.8'-22.5'' (48 - 58 cm) will be an excellent fit for preschoolers. HOW TO FIND OUT YOUR PERFECT HELMET SIZE? To figure out the correct helmet size, wrap a measuring tape around your head, keep the tape 1 inch above your ears, and level front to back (In most cases, you are now measuring the widest part of your head).