16x20x4 (3 5/8) Furnace Air Filters MERV 10 Pleated Plus Carbon 6 Pack rockwool These highly porous large stones

These highly porous large stones are lightweight

altering 315W CMH lamps output also shortens their lifespan

the M108S is a welcome addition and powerful trimming solution to a modern harvesting workflow

They reliably warm the root zone to 10ºF-20ºF above ambient air temperature

16x20x4 (3 5/8) Furnace Air Filters MERV 10 Pleated Plus Carbon 6 Pack rockwool These highly porous large stonesImportant 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 16x20x4 filter