20x25x5 (4 3/8) Lennox X6673_X6675 Replacement  MERV 8 Pleated Plus Carbon 4 Pack complete-systems Active Aqua air stones are

Active Aqua air stones are an ideal way to add oxygen to your hydroponic growing system

Great White is used by professional and home growers for its quality

Registered CDFA Organic Input Material

square wave technology provides excellent current stability and consistency in output levels

This fish-based fertilizer encourages beneficial microbes for better roots

20x25x5 (4 3/8) Lennox X6673_X6675 Replacement  MERV 8 Pleated Plus Carbon 4 Pack complete-systems Active Aqua air stones areImportant 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,