Fast Release Formula begins working immediately to eliminate foul odors caused by mold, mildew, pets, food, smoke and garbage. Each patented CLO2 Chlorine Dioxide generator pouch treats an area up to 1,000 Cubic Feet. It is the fastest and most effective solution for dealing with smoke or damp, musty odors. Ideal for cars, RVs and boat cabins. Professional strength NosGUARD is not a cover-up or a perfume fragrance of any kind. Chlorine dioxide gas destroys all odors, features perfume fragrances and leaves behind a crisp, clean scent that will quickly dissipate with fresh air.