All child's heads vary and choosing the correctly sized helmet for your child has no correlation to their age. Please ensure to measure your child’s head before selecting your size helmet Rear flashing light, easy fastening chin strap, adjustable chin strap, air vents, extra padding, logo, vehicles print design, buckle fastening Composition: Main: ABS. Lining: EPS foam Dimensions: 33 x 21 x 17cm. Medium: 55-58cm This helmet has been tested and approved according to European Norm (EN) 1078:2012+A1:2012. It conforms with regulation (EU) 2016/425 Colour: Blue MICRO SCOOTERS Deluxe Premium Vehicle Helmet Medium - Multi