Kids helmet tailored for active kids who enjoy cycling, accommodating head circumferences of 48-54cm In-mold polycarbonate microshell ensures a lightweight yet durable design, while the 10 air vents provide ample airflow during hot rides Chroma incorporates Energy Reduction Technology (ERT) - waffle-shaped pads designed to flex in multiple directions, effectively absorbing various types of impacts Micro-adjustable dial retention system ensures a secure fit, while the side and chin straps allow for fine-tuning, and the removable interior fit pads wick away moisture and are washable Complies with U.S. CPSC Safety Standard for Bicycle Helmets for Persons Age 1 and Older (Extended Head Coverage)