HEPA filter safely removes 99% of airborne particles as small as 0.3 microns, including pet dander, allergens, mold spores and dust particles. Compatible with Fellowes AeraMax Pet PT65 Air Purifier. With normal usage, it is recommended that you change your filter every 12 months to keep your air purifier running at peak performance. A filter change indicator on your Fellowes AeraMax Pet PT65 Air Purifier conveniently notifies you when it"s time to replace your HEPA filter.