US Home Filter SC60-20X24X4 20x24x4 Merv 11 Pleated Air Filter (3-Pack), 20" x 24" x 4" Actual size: 19-3/8 inch x 23-3/8 inch x 3-5/8 inch Merv 11 tested under ashrae 52.2-2007 standards Ideal for those with moderate allergies. Suspended/Fine Dust Protection Moisture resistant, heavy-duty Frame. Pollen Protection Galvanized expanded metal backing