Tear up the skate park wearing the Bell Adult Local Bike Helmet. The re-tuned shape offers a closer fit, while the Action Fit(TM) system allows you to fine tune the fit with a twist of the dial. It has 10 vents for airflow and a high-strength ABS hard plastic shell with an EPS liner. FEATURES: Bike and skate certified Action Fit(TM) system provides an adjustable, secure fit with the turn of a dial Ventilation: 10 vents ABS hard plastic shell with EPS liner Complies with U.S. CPSC Safety Standard for Bicycle Helmets for persons age 5 and older SIZING: S: 51 - 55cm M: 55 - 59cm L: 59 - 61.5cm