Abc or Multi-Purpose extinguishers utilize a specially fluidized and siliconized mono ammonium phosphate dry chemical. It chemically insulates Class A fires by melting at approximately 350°F and coats surface to which it is applied. It smothers and breaks the chain reaction of Class B fires and will not conduct electricity back to the operator. For Use on Class A (ordinary combustibles), Class B (flammable liquid) spills, and Class C (fires involving live electrical equipment).