Features EPS Core Equipped with thick EPS inner core to achieve great shock absorption and ensure great protection. Built-in soft inner headbands to prevent sweat from getting into your eyes. Ventilation System Comes with 9 vents designed to ensure all-around ventilation to prevent your head from overheating and bring a cool experience. Adjustable Strap The helmet has an adjustable strap to prevent it from falling off during sports, making it more comfortable during sports. Size Adjustment Button The helmet's adjustable buttons can be easily adjusted with one hand to make the helmet fit most head circumferences.