20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 8 Pleated Plus Carbon 2 Pack spl_spectrumking Protects grow chambers and nutrient

Protects grow chambers and nutrient solution from contamination by dust and debris

The Checker is the most popular pH meter in the world with over 1 million meters used since its introduction in 1991

and flower regulation

A simple fine mist spray is all it takes to maximize customer satisfaction and extend the enjoyment of receiving flowers

making it difficult for any dark green algae to form

20x20x5 (4 3/8) Honeywell/Lennox Replacement Furnace Filters MERV 8 Pleated Plus Carbon 2 Pack spl_spectrumking Protects grow chambers and nutrientImportant 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,