20x20x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 1 Pack beneficial microbes Minimum quantity to be ordered

Minimum quantity to be ordered of 3 pieces

then into your close loop pressure system

Size: 15''x19

the Bluelab pH Pen and Bluelab ppm Pen

always spill and mess free and is non-toxic

20x20x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 1 Pack beneficial microbes Minimum quantity to be orderedImportant 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