... -ply,3-ply, 2-ply, 1-ply 1)non-woven active carbon face mask with ear-loop,4-ply2 ... 25g)FunctionThe huge surface area of activated charcoal makes a large adsorption capability, which can absorb odorous gas, ... chemical enterprise and so on.Packing:1) packing:50pcs/box,2000pcs/ctn2) Packing size: 52*37*44cm, we ... very low resistance to breathing Disposable medical non-woven 4-ply active carbon face masks