Armor All FRESHfx Vent & Duct Cleaner Odor Eliminator is created specifically for automotive HVAC (Heating, Ventilation, Air Conditioning) systems. Armor All FRESHfx Vent & Duct Cleaner Odor Eliminator's special formula allows you to treat vents, ductwork, evaporator core and drain pan area, helping to eliminate a variety of odors. It cleans by removing light dirt that resides in ductwork and dirt and dust that sits on vent surfaces.