The NaturalAire Standard has an ASHRAE 52.2 rating of MERV 8. This filter is convenient to use and easy to replace. Ordinary furnace filters are designed to protect heating and cooling equipment from the insulating properties of relatively large airborne particles. The NaturalAire Standard goes far beyond that, removing even those microscopic particles that can stain walls and furnishings, or worseaggravate seasonal allergies. 16" x 25" x 1" NaturalAire standard pleated air filter 100% synthetic wire backed media Clay coated frame MERV rating 8 90 day filter Effective against pollen, dust/lint, dust mites, pet dander, mold, bacteria, virus carriers.