with self-priming dhl alternative k ship anti-dust pads adjustable activate carbon pm2.5 f wqyy

k anti-dust with self-priming with alternative pads mask adjustable and reusable mask j.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.