A ball valve is a form of quarter-turn valve that uses a pivoting ball that has been drilled through to control flow. When the hole is in line with the flow direction, it allows fluids or gasses to pass through. Alternatively, when the ball is turned 90 degrees, the flow is stopped completely. In either case, the handle serves as a visual indicator of the valve’s status. If the handle is parallel to the valve, it's open. In contrast, if the handle is perpendicular, the valve is closed.
