20x20x4 (3 5/8) Furnace Air Filters MERV 8 Pleated Plus Carbon 1 Pack grow-light-ballasts Direct replacement for Ona Carbon-Air

Direct replacement for Ona Carbon-Air (ON10052)

recycle timers

and then add water to create the ideal environment for the bacteria

Propagation of leafy greens

20x20x4 (3 5/8) Furnace Air Filters MERV 8 Pleated Plus Carbon 1 Pack grow-light-ballasts Direct replacement for Ona Carbon-AirImportant 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