dhl ship40 1 pcs fapad dust pm2.5 activate carbon filter non-woven mask replacement universal protective face mask gasket mat

40 1 pcs fapad non-woven mask replacement universal protective famask gasket mat for kf94 k 2.1.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.