Noble Mask Fabric Face Masks PM2.5 are perfect for protection against dust, pet dander, etc. Each mask comes with its own carbon filter. Our masks are made from 2 layers of high thread count woven cotton fabric that is soft and comfortable on the skin. The dense fabric is best suited for masks as it blocks much of the dust while being breathable. Noble Masks have a sleeve on the inside to insert the carbon filter. It is recommended to replace the carbon filter every 3-5 days of usage. But the mask is functional even without the filter (however, please note that it is the filter that blocks the PM2.5 particles). The elastic and adjustable ear loops are soft, comfortable and stretchy yet not irritating. They will stay put behind the ears. Our masks are made from cotton fabric so they are washable and reusable as many times as you want. Just remember to wash them by hand and line dry in the sun. We do not recommend them to wash in the washer or tumble dry (due to the snags on the elastic). Please remove the carbon filter before washing. Use them when you go out for grocery, or if you use public transport to commute or just as a safety precaution when you go out in public. These are made from attractive patterns that will look good on any face.