3M - 18'' x 24'' x 1'' Gray Dust Reduction Filtrete Filter

18'' x 24'' x 1'', Gray, Dust Reduction Filtrete Filter, 3 Month Filter, Electrostatically Charged Fibers Attract & Capture Large Airborne Allergens Like Pollen, Household Dust & Lint, Ideal For High Velocity Heating/Cooling Systems, Performs Better Than Ordinary Fiberglass & Washable 1'' Filters, For Residential Use Only, MPR Rating 300, Lasts Up To 3 Months.