... 180gsm, 220gsm Packing: 50pcs/box, 40boxes/case Disposable PP Dust mask,Spec.: 140gsm, 160gsm, 180gsm, 220gsm,Packing: 50pcs/box,40boxes/case ... ourselves. Our facemask(BEF over 99%) be proved can prevent virus availably,such as SARS(Severe Acute Respiratory Syndromes),H5N1(Avian ... Influenza, AI),H1N1(swine flu virus),etc As for the certificate, we have ISO, CE, ...