20x20x4 (3 5/8) Furnace Air Filters MERV 10 Pleated Plus Carbon 6 Pack air-purification Effective on a wide variety

Effective on a wide variety of insects

It is also oil-free and therefore does not clog the stomata

which can drastically impact nutrient uptake and yields

and pollinators when applied as directed

The dimmer knob allows growers to change the brightness level of both the veg and bloom lights from 0-100% allowing you to obtain perfect growth performance

20x20x4 (3 5/8) Furnace Air Filters MERV 10 Pleated Plus Carbon 6 Pack air-purification Effective on a wide varietyImportant 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