dhl ship50 pieces mouth gasket anti dust and spray mask mat replaceable 3 layers breathable filter pm2.5 insulation pad 1 bo k

50 pieces mouth mask gasket anti dust and spray mask mat replaceable 3 layers breathable insulation pad 1 bo k x.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.