activate pm2.5 fliter dhl activated shipmask replacement filter for carbon insert pack pr 4j9j

mask replacement fliter activated carbon insert pack protective mask inner pads breathable hy8000 u.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.