3M 9004IN Three Layers of Filter Particulate Respirator Mask | Ability To Filter Above 90 Percent Of 0.3-Micron Particulate Dusts | Can Be Folded When Not In Use And Slipped Easily Into The Pocket | Pack of 1 Mask Respirator Reusable, Washable  (White, Free Size, Pack of 1)

The 3M 9004 IN is a dust mask composed of three layers of filters. The outermost layer filters out the largest dust particles, the innermost layer preserves the respirator’s shape and the middle layer is composed of electrostatic filter media. It has the ability of this respirator mask to filter above 90 percent of 0.3-micron particulate dusts. Scientific research has proven that for all dust particles sizes, 0.3 micron dust are the most difficult to filter effectively.