A ball valve is a flow control device which uses a ball to control fluid flowing through it. It is open when the hole through the middle of the ball is in line with the flow inlet, and closed when it is pivoted 90 degrees by the valve handle, blocking the flow. Ball valves are durable, performing well after many cycles, and reliable, closing securely even after long periods of disuse. These qualities make them an excellent choice for shutoff and control applications.