20x20x4 (3 5/8) Pure Carbon Pleated Odor Reduction Merv 8 Furnace Filters 6 Pack hydro-x Dosages depend on your style

Dosages depend on your style of growing

Ultra high capacity instant dechlorinator

Unit Compatibility: 777119

Outstanding results controlling powdery mildew

Spectrum : Full Spectrum

20x20x4 (3 5/8) Pure Carbon Pleated Odor Reduction Merv 8 Furnace Filters 6 Pack hydro-x Dosages depend on your styleImportant 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