A brass ball valve is a form of turn valve which uses a hollow and pivoting ball to control flow through it. It is open when the ball's hole is in line with the flow and closed when it is pivoted 90-degrees by the valve handle.  The handle lies flat in alignment with the flow when open, and is perpendicular to it when closed, making for easy visual confirmation of the valve's status. Made of durable brass and it performs well after many cycles, and reliable, closing securely even after long periods of disuse.