A carbon dioxide extinguisher is a type of fire extinguisher that uses carbon dioxide gas to put out fires. It works by displacing oxygen around the fire, which is essential for combustion. This makes it effective for fires involving flammable liquids and electrical equipment, as it leaves no residue and does not conduct electricity. These extinguishers are typically identified by their black label and are available in various sizes. When using a carbon dioxide extinguisher, it is important to aim at the base of the fire and sweep from side to side to ensure complete coverage.