ROCKBROS Road Bike Helmet - M/L Sizes, 4 Colors for Men and Women Colors: Black - White / Blue - White / Yellow - Black / Pink - Blue Materials: PC Shell + EPS Inner Shell Head Circumference: M (55 - 58cm) / L (58 - 61cm) Weight: Approximately 250g Ventilation System The bicycle helmet is equipped with 18 large ventilation holes to ensure good breathability. Adjustable With the head - circumference adjustment knob on the bike helmet, you can adjust the right size for your head. Removable & Washable The sponge lining is removable, allowing you to wash and replace it, which facilitates cleaning. Thickened Chin Pad The chin pad is also removable and washable, comfortable and sweat - wicking, suitable for long - term use.