Aerterra 20x20x4 MERV 8 AC Furnace Air Filter (4-Inch Deep Pleat)
Built for 4-inch filter cabinets, the 20x20x4 deep-pleat MERV 8 air filter offers expanded surface area for everyday filtration of dust, pollen, lint, dust mites, and mold spores. The deeper design lowers airflow resistance and lasts far longer than a 1-inch filter — often 6 to 12 months. Sold individually or as a case pack.