The package consist of four (5) filters. One (1) filter can last up to 14 days depending on usage and environment. Each filter has 5 layers.
1.The first layer: spunbond cloth, filter the dust of micron
2.The second layer: to filter industrial pollutants, automobile exhaust, second-hand smoke pollen allergies
3.The third layer: activated carbon cloth, benzene and a smaller function of filtering dust microns
4.The fourth layer: filter density, smaller material
5.The fifth layer: Spunbond cloth, filter out all kinds of harmful substances;
6.Application: hospitals, out, site, tourism, colds, operating workshops, farms, haze weather, cold and warm