20x25x1 Electrostatic AC Furnace Air Filter Gold 82% Arrestance. Low Resistance. Never Buy a New Filter All Standard filters are undercut 3/8 inch, Replaces disposable furnace filters, Self-charging electrostatic filter media - does not require electricity, Lifetime warranty The air you breathe contains many irritants such as pollen, dust, bacteria, mold spores, pet dander and smoke. Most of these particles are smaller than one micron. Our ELECTROSTATIC FILTER is an effective and efficient way to reduce the number of these particles in your air. This unique characteristic improves air flow while providing maximum filtration. Your satisfaction is 100% guaranteed or your money back in 30 days risk free trial. Lifetime Warranty Never Buy Another Filter. Electrostatic and HEPA Air Filters. We offer permanent, metal-framed Washable Electrostatic filters. We are in the Indoor Air Quality business Very Low Air Resistance. Arrestance 82% These filters retail elsewhere for $ 99.99