The AlpinePure ET creates an active electric field to capture airborne particles with efficiencies of 97% at 0.30 microns. Electronic media air cleaners do an excellent job of removing submicron particles by the process of agglomeration—polarized particles bond with other charged particles in the air and are easily removed through the filter. Carbon center screens are included to trap odors and volatile organic compounds. The AlpinePure ET is a media is easy to replace. Unlike other electronic air cleaners, the AlpinePure ET creates no harmful ozone or annoying “zapping” noises. Assembled in the USA! QTY 1 is a 3 pack