MULTI-SPORT: Flybar helmets for adults and teens are adaptable for multi-indoor and outdoor activities including Inline and rollerblade skating, BMX, bike, Pogo, skateboarding and scooter DURABLE: Made of high-quality ABS shell, high-density EPS foam inner shell with 1-inch thick shock-absorbing foam SIZE CHART: For a perfect fit, measure the circumference of your head. S/M (53-55cm/20.8-21.6in); M/L (55-58cm/21.6-22.8in); L/XL (58-61cm/22.8-24in) Features an adjustable spin dial to ensure a safe and snug fit DESIGNED FOR MAXIMUM COMFORT: With a special aerodynamic design, 12 vents circulate air, keeping your head cool and reducing sweating MACHINE WASHABLE: Removable pads are washable and quick-drying. Easy to wash the sweat away