20x25x4 (3 5/8) Furnace Air Filters MERV 8 Pleated Plus Carbon 2 Pack Environmental Controllers Whether you're running a commercial

Whether you're running a commercial greenhouse or tending a backyard garden

Patent-Pending dual impeller design pumps water on one end and generates oxygen on the other

Reduces biofilm - Keep lines clear of dangerous organic material

This state of the art fixture uses the highest quality Samsung diodes

Helps stimulate flower development in the final bloom stage

20x25x4 (3 5/8) Furnace Air Filters MERV 8 Pleated Plus Carbon 2 Pack Environmental Controllers Whether you're running a commercialImportant 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