amerex b500, 5lb abc dry chemical class a b c fire extinguisher (2) amerex 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. 6-year manufacturer’s warranty stored pressure design dependable drawn-steel cylinders durable high-gloss polyester powder paint all-metal valve construction temperature range -65°f to 120°f