Different types of fires require different types of extinguishers. Class A extinguishers are designed to extinguish fires involving ordinary combustibles such as wood or paper. Class B extinguishers are designed to extinguish fires involving flammable liquids such as gasoline or oil. Class C extinguishers are designed to extinguish fires involving electrical equipment. Class D extinguishers are designed to extinguish fires involving flammable metals. Class K extinguishers are designed to extinguish fires involving cooking oils and fats.