Tennessee Valley Apothecary's allergy blend "Quattro" is a convenient, ready to use pre-diluted roll-on bottle of a carefully researched synergistic blend of essential oils that are designed to promote free breathing during seasonal allergies and when threatened by common allergens. Quattro is based on a classic allergy blend that has been modified to be more effective at reducing sinus congestion, opening nasal passages, and providing extra support against sinus infections.* This product is typically used by applying over the sinuses or just outside the nostrils.