These filters are designed specifically for masks with dual valves, and they even have a little hole cut in the side to accommodate the valves . They're made from five-layers including an activated carbon layer, which will filter out most major allergens like dust and pollen.

5 Layer of protection filtering

1. First layer of spun-bonded cloth filters micron-level dust
2. Second layer filters industrial pollutants, automobile exhaust, second-hand smoke, and pollen allergens
3. Third layer of activated carbon cloth filters micron-level dust
4. Fourth layer offers filter density for smaller material
5. Fifth layer of spun-bonded cloth filters out all kinds of harmful substances

Contents:

3x 5 Layer Replacement Filter For Dual Valve Sports Mask