KN95 masks are useful for preventing novel coronavirus pneumonia infection.KN95 masks have a three-layer structure that filters out the novel coronavirus, and the masks are more airtight, which prevents novel coronavirus pneumonia infection.In addition to preventing general novel coronavirus pneumonia infections, KN95 masks can also be used for medical personnel, fever clinic personnel KN95 masks can also be used for medical personnel, fever clinic personnel, nucleic acid collectors, nucleic acid testing personnel, or personnel who are in contact with confirmed or suspected patients with novel coronavirus pneumonia. When wearing the mask, it is important to pay attention to the correct method, and should be replaced in a timely manner, if the mask becomes wet through exhalation, then the protective effect will be reduced, and should be replaced in a timely manner, it is generally recommended that it be replaced once every 4-6 hours.