20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 13 Plus Carbon 4 Pack grow-system/-trays/-reservoirs -Maximum cfm: 580

-Maximum cfm: 580

LTL Controls CO2 Generators come with everything you need to get your CO2 system started

non-slip base

Two strips in array per shelf

20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 13 Plus Carbon 4 Pack grow-system/-trays/-reservoirs -Maximum cfm: 580Important 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,