US Home Filter SC40-18X30X1-6 18x30x1 Merv 8 Pleated Air Filter (6-Pack), 18" x 30" x 1" Actual size: 17-5/8 inch x 29-5/8 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