20x25x4 (3 5/8) Pleated MERV 15 Air Filters 6 Pack ventilation/air-conditioning The concentrate is made from

The concentrate is made from 100% pure

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It is suitable for both indoor and outdoor growing but is most recommended for indoor use for crops requiring a lot of water

15 foot (CSXCORD) and 25 foot (CSXCORD25) options

20x25x4 (3 5/8) Pleated MERV 15 Air Filters 6 Pack ventilation/air-conditioning The concentrate is made fromImportant 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