Fire Extinguisher Cylinders are pressurized containers that hold the extinguishing agent in a fire extinguisher. These cylinders are made of steel, aluminum, or composite materials, and are designed to withstand the high pressure of the extinguishing agent. The cylinder is a critical component, as it is responsible for storing & containing the extinguishing agent until it is needed. Fire Extinguisher Cylinders are designed to withstand high levels of pressure & impact, as well as extreme temperatures.