20X25X5 (19_3/4 X 24_3/4 X 4_3/8) Lennox X6673_X6675 Replacement MERV 12 Air Fil
Model Number 20x25x5 LXRED. Important Note: Almost ALL furnace filters have a different “actual size” than the nominal size printed on the air filter. With the 4″ and 5″ air filters there is a wider variance depending on the manufacturer.