20x20x5 (4 3/8) Honeywell/Lennox Replacement MERV 12 Air Filters 4 Pack X Nutrients bloom Gives plants better resistance to

Gives plants better resistance to pest nematodes

while the single-bucket Root Spa systems use a single dedicated air pump

this bacterium will overcome any pathogenic spores present

Upgrade your Sunburst reflector with this optional lens system

20x20x5 (4 3/8) Honeywell/Lennox Replacement MERV 12 Air Filters 4 Pack X Nutrients bloom Gives plants better resistance toImportant 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. We also carry 4 7 8 and 5 1 4 inch depth filters,