A valve is a device used to control the flow of fluids (liquids, gases, or slurries) through a pipe or other passage by opening, closing, or partially obstructing the flow. Valves come in various types, such as gate valves, ball valves, check valves, and butterfly valves, each designed for specific applications. They are used in industries like water treatment, oil and gas, chemical processing, and manufacturing. Valves play a critical role in regulating pressure, directing flow, and ensuring the safe operation of systems in both industrial and domestic settings.