Features SKATEBOARD HELMET FOR KIDS: ASTM & CPSC CERTIFIED Kids skateboard helmet is optimized for comfort and impact resistance with reinforced ABS SHELL & shock-absorbing EPS core. EXTRA REMOVABLE LINING The adjustable kid's skateboard helmet has two removable liners for different head sizes and easy-to-wash material. DOUBLE ADJUSTMENT Well-attached & long-lasting adjustment dial & chin strap with skin-friendly material for the best fit and comfortable skateboarding and cycling experience. PROFESSIONAL VENTILATION SYSTEM It is equipped with 12 air vents that will KEEP YOU COOL and comfortable for hours of riding. 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).