20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 12 Pleated Plus Carbon 1 Pack fans-ventilation-ducting works well with all systems

works well with all systems and may be used during all stages of growth

No additional additives required

Benefits of Root Cleaner:

humidity and CO2 control

odor and VOCs

20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 12 Pleated Plus Carbon 1 Pack fans-ventilation-ducting works well with all systemsImportant 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,