Replacement PM2.5 Activated Carbon Multi-layer filter. • Dimensions: Size of Filter: 4.7''x3.1''. • Materials: 5 Layer Filtration technology: filters are Made of activated carbon and non-woven melt-blown filter cloth, five-layer filter system effectively keep away from a range of airborne contaminants, Dust, Haze, Allergies, Smoke, Pollution, Ash, Pollen, hazardous chemicals, heavy metal particles etc. • Includes: 10 Multi-layer filters • How to use: Insert the PM2.5 filter along the inside pocket of your face mask • Disposable, cannot be reused or washed. It is recommended to replace filters every 3 to 7 days depending on amount of usage • Additional Information: Non-medical face mask – please see CDC.gov for further information *Due to the nature of the product, all sales are final and we will be unable to accept returns.