The ABC dry powder fire extinguisher contains a dry chemical powder that can tackle fires involving ordinary combustibles (Class A), flammable liquids (Class B), and fires caused by electrical equipment (Class C). This type of extinguisher typically uses a dry chemical powder composed of monoammonium phosphate or a similar substance to smother the fire by interrupting the chemical reaction of the fire triangle, effectively extinguishing the flames. It's a versatile and widely used fire extinguisher suitable for various types of fires commonly encountered in different settings.