AFFF (Aqueous Film Forming Foam) Fire extinguishers offer some additional benefits over water units. Not only do they typically have higher fire ratings, but they are also suitable for Class B fires involving flammable liquids, as well as Class A fires, those involving combustible materials. They are highly effective fire extinguishers with a rapid flame knockdown, and do not compromise visibility for safe building evacuation. Corrosion resistant finish. Spray nozzle.