20x20x4 (3 5/8) Pleated MERV 8 Air Filters 1 Pack Light Fixture has a high cation exchange

has a high cation exchange rate with potassium

rock powders and micronized leonardite

Stack count: 5

Never before has there been a pH controller with these features for this value

20x20x4 (3 5/8) Pleated MERV 8 Air Filters 1 Pack Light Fixture has a high cation exchangeImportant 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