The Reusable pollen filter captures dust, pollen, mold spores, pet dander, and more with an 88% efficiency at 7-10 microns. These filters are industry standards and will protect your machine. The filter should be rinsed with clean tap water every 2-4 weeks to assure the highest performance in Dream Station Go. Clean with running tap water to allow the water to clear any collected debris accumulated on the filter. Only place the filter back in the Dream Station Go when completely dry. This product comes with 6 replacement and reusable pollen filters.