Triple action purification system. patented hemi-spheric hepa type filter removes smoke, pollen and dust, the uv germicidal light kills airborne bacteria and germs and the photo catalyst filter reduces harmful toxic paint, carpet fumes and other household chemicals. includes a 3-speed fan, uv/voc on/off button, 24 hour timer, clean filter indicator and easy to read digital display. no costly filters to replace. energy star certified. for medium sized rooms.