The KN95 mask is one of nine particulate protective masks certified by NIOSH. "N" means not resistant to oil. "95" indicates that the particle concentration in the mask is more than 95% lower than that of the particles outside the mask when exposed to the specified number of special test particles. The 95% value is not the average value, but the minimum value. KN95 is not a specific product name, as long as it meets the KN95 standard and passes the NIOSH review, it can be called "KN95 mask". The protection level is KN95, which means that under the detection conditions specified by the NIOSH standard, the filtering efficiency of the mask filter material for non-oily particulate matter (such as dust, acid mist, paint mist, microorganisms, etc.) reaches 95%.