US Home Filter SC40-20X20X1-6 20x20x1 Merv 8 Pleated Air Filter (6-Pack), 20" x 20" x 1" Actual size: 19-1/2 inch x 19-1/2 inch x 3/4 inch Merv 8 tested under ashrae 52.2-2007 standards Ideal for normal air filtration and those with mild allergies Moisture resistant, heavy-duty Frame Galvanized expanded metal backing