Tier1 Replacement for 20x24x1 Merv 13 Ultimate Air Filter/Furnace Filter 6 Pack Similar to the 3M Filtrete Healthy Living Ultimate Allergen 20x24x1 Air Filter Made in the U.S.A. Actual Size: 19 1/2 inches (length) x 23 1/2 inches (width) x 3/4 inches (thickness) Electrostatically charged filter media 3 Month Filter Life