20x25x4 (3 5/8) Furnace Air Filters MERV 10 Pleated Plus Carbon 2 Pack Hydroponics Yet it's small enough to

Yet it's small enough to be maneuverable

There will not be contamination when outsourcing plant starts and clones

Photocell deactivates CO2 device during night cycle

Male - IP68

achieve maximum quality and quantity

20x25x4 (3 5/8) Furnace Air Filters MERV 10 Pleated Plus Carbon 2 Pack Hydroponics Yet it's small enough toImportant 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 20x25x4 filter