Class A
A fire extinguisher labeled with letter "A" is for use on Class A fires. Class A fires are fires that involve ordinary combustible materials such as cloth, wood, paper, rubber, and many plastics.

Class B
A fire extinguisher labeled with letter "B" is for use on Class B fires. Class B fires are fires that involve flammable and combustible liquids such as gasoline, alcohol, diesel oil, oil-based paints, lacquers, etc., and flammable gases.

Class C
A fire extinguisher labeled with letter "C" is for use on Class C fires. Class C fires are fires that involve energized electrical equipment.

Class D
A fire extinguisher labeled with letter "D" is for use on Class D fires. Class D fires are fires that involve combustible metals such as magnesium, titanium and sodium.

Class K
A fire extinguisher labeled with letter "K" is for use on Class K fires. Class K fires are fires that involve vegetable oils, animal oils, or fats in cooking appliances. This is for commercial kitchens, including those found in restaurants, cafeterias, and caterers.