A shutoff valve is a mechanical device used to control the flow of liquids or gases in a piping system. It can be opened or closed to either allow or stop the passage of the substance, making it essential for managing water supply in homes, industrial processes, and various applications. Shutoff valves come in different types, including ball valves, gate valves, and globe valves, each designed for specific functions. These valves are typically installed at key points in a plumbing system, such as near the water meter or appliances like water heaters and faucets. By turning the valve handle, users can quickly stop the flow in case of leaks or maintenance, ensuring safety and efficiency in the system.