A fuel tank is a container designed to hold flammable fluids, primarily gasoline or diesel, for use in vehicles and machinery. Fuel tanks are generally made out of durable materials such as metal or high-density polyethylene, ensuring they can withstand the pressures of storage, transport, and the corrosive effects of fuel. They come in various shapes and sizes depending on their application, with features that can include multiple access ports for pumping and refueling. The tank must maintain a sealed environment to prevent leaks and evaporation, often incorporating safety mechanisms to ensure safe handling of volatile substances.