20x20x4 (3 5/8) Pleated Air Filters MERV 14 Plus Carbon 1 Pack light The pH electrode uses a

The pH electrode uses a unique reference cell design that utilizes an extractable cloth junction

For peace of mind

The premium granules expand up to 7 times in volume when hydrated as needed

We recommend the Super Green LED to be placed a minimum of 4 feet away from your plants

TableTop Brush

20x20x4 (3 5/8) Pleated Air Filters MERV 14 Plus Carbon 1 Pack light The pH electrode uses aImportant 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 20x20x4 filter