dhl ship5 layers child pads insert mat activated replaceable s pad cotton pm2.5 activate carbon mask filter zza2066

5 layers child mask pads insert mat activated carbon replaceable s pm2.5 mask pad zza2066 w.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.