Accumulair Carbon 20x20x1 (19.5x19.5) Odor eliminating Air Filter/Furnace Filter Nominal Size 20x20x1. Actual Size 19.5 x 19.5 x 0.75 A simple solution for controlling both odors and dust particles Ideal applications include odors from cooking, new paint, new carpet, bathroom smells, and smoke Can be installed in virtually any HVAC system without modifications Lasts up to 90 days