Your Kelvinator humidifier system uses the foam filter pad listed below that is a cut-to-fit style that is trimmed to the size needed. Approximate size of this filter pad is 6″ x 65″ x 3/8″. This is used in your system to collect pollutants before allowing clean, moist air to be circulated within your house to increase the level of humidity in the air. It is recommended that your filter be changed one to two times per season, depending on level of usage.