HealthyClean Solid provides continuous protection against a variety of bacteria, viruses, molds, mildew and yeasts in the indoor environment, yet is safe to use around people and pets. Atlhough this product may be used alone, it is most effective when used in combination with our HVAC fogging service. To use, just remove the lid and place the tub inside the furnace cabinet where the filtered air can pass over it. Easy to install, this product performs well, has a nice, fresh scent and lasts for months. To order, contact HealthyAir customer service: 1-877-724-7872.