These products eliminate unpleasant odors from indoor spaces. These products are odor neutralizers, not perfumes or cover-ups. That means that the product chemically reacts with bad-smelling particles in the air and neutralizes their scent. They can be used in homes, basements, locker rooms, cars, boats, and any other space that needs refreshing, and come in a variety of sizes. They can neutralize the smell of smoke, mold, mildew, cat litter, and pets, as well as the noxious smells created by formaldehyde hydrogen sulfide and other chemicals. Note that these products do not improve indoor air quality—their use is to neutralize odors and they are not a substitute for taking steps to improve ventilation and remove sources of bad odors such as mold and mildew.