#CLAIR OFFICIAL STORE# Replacement filter for CUBE Plus air purifier. We recommended to change the filter once a year. 1. E2F filter - Most pollutants have polarity. The Clair air purifier collects (+), (-) polarity on both sides of the filter as the indoor air that will be contaminated passes through the e2f filter, attaching a magnetically polarized pollutant. 2. Deodorizing Filter - The activited carbon filter can remove harmful substances and odors.