20" x 20" x 1", Gray, Dust Reduction Filtrete 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, Filter Lasts For 90 Days.
