Ideal for use in offices, warehouses, homes and more, Amerex’s ABC Dry Chemical  Fire Extinguishers use a monoammonium phosphate dry chemical to insulate Class A fires by melting and clinging to the heated surface. They also smother and break the chain reaction on Class B fires and are non-conductors of electricity. Units have a 21/2 to 20 lb capacity range. FM approved, except for models AX402, AX402T and AX424. USCG approved