This model air purifier incorporates a 3-stage cleaning system to help clean the air that passes through the filter in the unit. Stage 1:Washable or Odor & VOC Reducing Pre-Filter attaches to the rear grille. Captures larger airborne particles and traps odors. Stage 2:Permanent Washable iFD® Filter. Captures the following microscopic airborne particles: dust, pollen, pet dander, dust mite debris and smoke. Stage 3:Electronic Ionizer boosts the cleaning power. This model earned the Energy Star. The purifier in perfect working condition. Replacement Filter and manual are available.