fliter face dust mouth safe breathable 3layer original mask replacement pm2.5 activate carbon f p5ap

3layer fliter safe dust breathable mouth famask replacement pad comfortable pad l.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.