The car air purifier uses HEPA filter - H13 filter. It has 3 layer filter - Pre-filter, H13 HEPA filter, and carbon activated filter, guaranteeing 99.97% of particle removal. The built-in anion generator produces negative ions to charge particles and trap them and give your air a fresh feel. It is highly efficient for all vehicles up to 7 seaters and other small space. Approved CE,ROHS,WEEE, FCC certification and global patent protected.