FEATURE: Bicycle Helmet has a headlight and a taillight. A light-up helmet makes you that much more visible to cars on the road. Also, our USB-rechargeable helmet make you much safer to ride at night with its white LED headlight and red taillight. IMPACT-RESISTANCE:This bike helmet is specially designed for adult rider. Material use the durable PVC PC, EPS foam which help absorb the impact and protect the head during crash. VENTILATION: The bike helmet has 20 air vents, which helps keep your head cool whether youre biking to work, road cycling, or traversing bumpier routes. LIGHTWEIGHT: The helmet only weight 320g and 300 g. It is a good ride-around-town kind of helmet. You may forget it was on your head during the ride because of its lightweight and ventilation. ADJUSTABLE: There is a 360-degree size adjustment system that makes it easy to find the perfect fit. It is perfect for women and men. There is two size for you M(54-57CM)L(58-60CM) You can measure your head circumference and choose the size from our size chart.