Product Description The AAF Flanders NaturalAire Elite Air Filter removes the greatest amount of airborne particles and is made of a one-sided metal-reinforced pleated media. This filter tests as a MERV (Minimum Efficiency Reporting Value) 13 rating through ASHRAE 52.2 testing methods. MERV 13 filters are the appropriate application in general surgery, hospitals, and health care facilities. Now you can have a MERV 13 quality air filter in your home. Housed in a recyclable clay-coated moisture resistant frame, the NaturalAire Air Filter uses a mechanical media that maintains the minimum listed efficiency through the 90-day service life of the filter. This filter captures particles as small as 1 microns and is effective against the following contaminants: household dust, pollen, dander, lint, smoke, smog, bacteria, as well as lead dust and microscopic allergens. From the Manufacturer The NaturalAire MERV 13 is in the top tier of filters for contaminant removal in residential retail air filters. National Air Filtration User's Guide for ASHRAE Standard 52.2-2007 shows MERV 13 filters are the appropriate application in general surgery, hospitals, and health care facilities. Now you can have a MERV 13 quality air filter in your home.