20x25x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 1 Pack Environmental Controllers A pair of liquid-filled stainless

A pair of liquid-filled stainless steel pressure gauges tell you when it’s time to change the pre-filters

Potassium Bicarbonate (baking powder)

durable humidity control

• Improves nutrient and water uptake

Luxx NX-1 Controller

20x25x4 (3 5/8) Furnace Air Filters MERV 12 Pleated Plus Carbon 1 Pack Environmental Controllers A pair of liquid-filled stainlessImportant 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