A gas cylinder is a container designed to hold gases under pressure. These cylinders are typically made of steel or aluminum and come in various sizes, depending on their intended use. They are commonly used in industries, laboratories, and for household purposes, such as cooking or heating. Gas cylinders are equipped with safety features, including pressure relief valves and protective caps. They can store different types of gases, such as oxygen, propane, or carbon dioxide, and are essential for applications like welding, medical treatments, and beverage carbonation. Proper handling and storage are crucial to ensure safety.