16x20x4 (3 5/8) Pure Carbon Pleated Odor Reduction Merv 8 Furnace Filters 6 Pack Travel Bags & Backpacks • Improves nutrient absorption rates

• Improves nutrient absorption rates

Now comes in a bulk pack too

European Red Mite (Panonychus ulmi)

3 gallon aluminum vacuum chamber

humic acids

16x20x4 (3 5/8) Pure Carbon Pleated Odor Reduction Merv 8 Furnace Filters 6 Pack Travel Bags & Backpacks • Improves nutrient absorption ratesImportant 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 16x20x4 filter