Regardless of whether it is a disposable face mask or a medical mask, there are actually front and back sides. Take a disposable respirator for example, the darker color is the front side, and the front side should face outward, and there are metal strips on the nose clip on the medical mask. The face facing the face should be the reverse side of the medical mask, that is, the lighter side. In addition, it should be noted that the part with the metal strip should be on the top of the mask. Don't wear it backwards. After distinguishing the front, back, upper and lower ends of the disposable mouth mask, wash your hands first, and after confirming whether the face mask levels are correct, hang the elastic cord for masks at both ends on your ears. After wearing the Chinese mask, you need to press the metal strips on both sides of the bridge of the nose with both hands to make the upper end of the mask close to the bridge of the nose, and then stretch the mask downwards so that the mask does not leave any wrinkles, and it is best to cover the nose and mouth.