dhl ship pm2.5 s for n90 safety mouth face mapm2.5 sk replacement pad square replaceable mat

s for n90 safety mouth famask replacement pad square replaceable mat a.1.the first layer: high efficient filter cloth filter the dust of micron.2.the second layer: meltblown cloth to filter industrial pollutants, automobile exhaust, second-hand smoke pollen allergies.3.the third layer: high efficient filter cloth filter benzene and a smaller function of filtering dust microns.4.the fourth layer: activated carbon cloth filter density, sma.