20x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 2 Pack nutrient-combo A ventilation ducting tool designed

A ventilation ducting tool designed to fit different-sized duct hole openings together

Either feed as unhatched pupae or as hatched adult flies

Want to switch from rockwool to coco without altering their grow workflow

A Natural Isolate From the Amazon - Azos is a particularly-efficient agent originally isolated in the Amazon Basin where the lack of soil

20x20x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 2 Pack nutrient-combo A ventilation ducting tool designedImportant 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