5 layers dhl activated adults shippm2.5 carbon pm2.5 kid protective insert for mouth mask xe9k

pm2.5 activated carbon adults 5 layers insert protective insert for mouth mask dust-proof filtration pad ooa7814 e.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.