20x25x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 2 Packs grow-light-ballasts Increases resistance to environmental stress

Increases resistance to environmental stress

This function benefits the overall health of the root zone by mitigating the chances of pathogens establishing in the grow media

an extract of the neem tree

the fixture to produce a class leading output

20x25x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 2 Packs grow-light-ballasts Increases resistance to environmental stressImportant 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