20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 13 Plus Carbon 4 Pack Grow System/ Trays/ Reservoirs blue-red spectral combination specifically designed

blue-red spectral combination specifically designed for stacked grow architectures

Verticillium sp and White Mold

Shoe covers are designed with a non-skid sole that helps reduce the risk of slips or falls

non-pathogenic saprophytic fungus isolated from plant material

Includes PGZ18 5kV socket

20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 13 Plus Carbon 4 Pack Grow System/ Trays/ Reservoirs blue-red spectral combination specifically 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. We also carry 4 7 8 and 5 1 4 inch depth filters,