20x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 6 Pack bio soil Autopilot's digital CO2 controller eliminates

Autopilot's digital CO2 controller eliminates guesswork while it controls your carbon dioxide level with accuracy and efficiency

Fits Powerhouse (all)

Includes a quality UL-listed water pump with pre-filter housing to keep sprayers free from debris and preventing clogging

Sodium Bicarbonate (baking soda)

20x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 6 Pack bio soil Autopilot's digital CO2 controller eliminatesImportant 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