The masks are disposable medical masks, medical surgical masks or above protective level masks. As a reminder, gauze and other cloth masks cannot be used for medical protection. Different types of masks are required for different occasions. When taking public transportation such as buses, subways, coaches and trains, and when in public places with poor ventilation such as shopping malls and theaters, you should wear disposable medical masks or medical surgical masks. If you have fever, cough or other respiratory symptoms, you should wear a medical surgical mask or a protective mask without a breathing valve that meets the KN95/N95 level or above.