 that seek out and destroy odors underneath, behind stuff. You don't have to buy filters all the time. That's going to save you a bunch of money as well. Start enjoying your home again. Get several of these. We've got three in the PAGS house, and it really does help out. You know where they are because it smells like clean, fresh air after a thunderstorm where that unit is plugged in. Save $200 on an Eden Gear Thunderstorm 3-pack for the entire home.