DESC: Peaceful Breeze™ Model 681 large room air purifier uses a combination of filtration processes to provide you with a HEPA filter air purifier, an activated carbon filter air purifier and/or an ionic air purifier all in one unit. The negative-ion generator, photo-catalyst pre-filter, HEPA filter, activated carbon filter and optional herbal sterilization filter combine to eliminate and absorb household odors, smoke, germs and harmful gases.