Fellowes 0 True HEPA Filter with AeraSafe Antimicrobial Treatment, White True HEPA Filter captures 99.97% of airborne particles as small as 0.3 microns AeraSafe antimicrobial treatment provides built-in protection from the growth of odor causing bacteria, mildew and fungi on the True HEPA filter Compatible with Fellowes AeraMax 300 Air Purifier. This items packaging will indicate what is inside and cannot be hidden. 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 300 Air Purifier conveniently notifies you when it's time to replace your True HEPA filter