20x25x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 2 Pack drying-racks On-screen tutorial messages for calibration

On-screen tutorial messages for calibration

Re-attach the lid

Adjust and review your CO2 levels when you want to and how you want to

EC-to-TDS Conversion Factor: NaCl (avg of 0

We recommend that you change your air filter every 3-6 months to maintain maximum efficiency and economy

20x25x4 (3 5/8) Pleated Air Filters MERV 15 Plus Carbon 2 Pack drying-racks On-screen tutorial messages for calibrationImportant 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 20x25x4 filter