20x20x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 1 Pack beneficial microbes Store product in original container

Store product in original container and keep in a cool dry area – below 100F

one 8 oz CaMg+

discard after 2 weeks

5 meters of 1/4"

20x20x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 1 Pack beneficial microbes Store product in original containerImportant Note: Almost ALL furnace filters have a different "actual size" than the nominal size printed on the air conditioner filter. It's best if you measure your air filter for the EXACT size and compare it to our "Actual Size" and then you can be sure your A C air filter fits! With the 4" and 5" air filters there is a wider variance between the nominal and actual size depending on the manufacturer. If you are replacing a 4 3 8 depth 20x20x4 filter