Kn95 is a mask with a breathing brake. It refers to the respirator which meets the national standard of China gb2626-2006, and the protection efficiency of non oily particles is not less than 95%. This kind of mask can effectively protect the particles suspended in the air, and its tightness is good, so it is the best choice during the epidemic period.The function of the breathing valve is to work in a hot and humid environment with poor ventilation or a large amount of labor. Using a mask with a breathing valve can help you feel more comfortable when you exhale.