Bern Nino Summer Helmet with Visor Certified ASTM F 2040, CPSC and EN 1078 Low Profile Fit Doesn't look like a spaceship landed on your head! Adjustable fit system at back of head Zipmold foam compatible to upgrade a winter liner (sold separately) for winter sports Fits Heads 48-51.5 cm in circumference. Generally Ages 2-5, but definitely measure your child's head for best fit