Ball valves are shutoff valves that use a ball to stop or start the flow of fluid downstream of the valve. The ball performs the same function as the disc in other valves. As the valve handle is turned to open the valve, the ball rotates to a point where part or the entire hole that is machined through the ball is in line with the valve body inlet and outlet. This allows fluid flow to pass through the valve. When the ball is rotated so that the hole is perpendicular to the flow path, the flow stops.