1) non-toxic,harmless, no sensitive reaction 2)Original quality, much lower price 3)0.3um dust can ... filter Application:1). Air HFPA purifier, air filter bags etc.2). Medical nano silver mask, exposure suits, hygiene necessities.Remark:1 ... Material can be Selected according to customer's requirement2.Prefilter net can be added on the surface of hepa to prolong ...