DIY Face Mask Filter Media provides an added layer of protection to homemade and store-bought face masks. In fact, it’s the same 100 percent polypropylene needle punched material that we sell to commercial face mask producers (i.e. medical, dust, paint, etc.). This vital filtering layer previously only available to the commercial sector, is now available to you! The material contains an electrical charge to capture particles in the air. Use the filter media as an inside/interfacing layer of a sewn mask or as a removable filter for pocketed masks. Each flat-pack contains a 24 inches by 3-yard section of filter media that can be cut to any size. Typically, each pack has enough filter material to make approximately 108 filters sized 4 inches x 6 inches. Machine washable, lay flat to dry. To iron, use low heat and a pressing cloth for best results.