With fan, three-level air volume. Three gears are set according to people's sitting, walking and running, so that people can enjoy fresh air comfortably anytime and anywhere. With valve, the valve is closed when inhaling to prevent polluted air from entering; the valve automatically opens when exhaling to discharge carbon dioxide. USB charging, charging for 4 hours, battery life for 6-8 hours. High-efficiency composite filter element. Uses: anti-fog, anti-PM2.5 particles, dustproof, anti-pollen, anti-secondhand smoke, anti-formaldehyde, , etc. Scenes: outdoor sports, hospitals, public places, various entertainment venues and office buildings, etc. Colour:White Material:plastic Package Contents: 1 x cycling mask Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.