The Guardian Air QR+ is an in-duct air purifier capable of purifying every cubic inch of air that your central heating and air conditioning system reaches. Proven to eliminate bacteria, viruses, mold and VOCs, the Guardian QR+ is also very effective at reducing unwanted odors from cooking, cleaning chemicals, pet areas, smoke and musty air. Say goodbye to smelly, stuffy, musty rooms and hello to fresh, clean, pure air throughout your home or office building.