The latest Micro helmets are designed for a firm ergonomic fit for the ultimate in safety. Lightweight with inbuilt ventilation the protective helmet is made for comfort on both long and short adventures. Parents can have peace of mind about their kids scooting both near and far. For sizing, measure the circumference of the head from the forehead where the helmet will sit, across the furthest point on the back of the head. PLEASE DO NOT GUESS. [S] Small: 48-53cm [M] Medium: 52-56cm - Adjustable chin strap - Interior padding for comfort - Integrated LED light - Certified AS/NZS 2063:2008+A1:2009 Bicycle Helmet WARNING - KEEP BUTTON BATTERIES OUT OF REACH OF CHILDREN Swallowing may lead to serious or fatal injury in as little as 2 hours, due to chemical burns and potential perforation of the esophagus. Never allow children to replace button batteries of any device. If you suspect your child has swallowed or inserted a button battery, immediately call the 24-hour Poisons Information Centre on 13 11 26 (Australia) or 0800 764 766 (New Zealand) for fast, expert advice. Regularly examine devices and make sure the battery compartment is correctly secured, e.g. that the screw or other mechanical fastener is tightened. Do not use if compartment is not secure. Dispose of used button batteries immediately and safely out of reach of children. A battery can still be dangerous even when it can no longer operate the device. Tell others about the risk associated with button batteries and how to keep their children safe.