A ball valve is a valve that is designed using a round disk to control flow through it. The ball valve’s round disk has a hole through the middle of it which allows for the flow of fluid and gas. When the valve is closed the round disk’s hole is turned is perpendicular to the ends of the valves blocking the flow, when the ball valve is open the round disk’s hole is turned parallel to the ends of the valve allowing flow through the hole. The handle on ball valves allow a visual for you to see if the valve is on or off, just like the port if the handle is turned perpendicular to the valve the flow is shut off, if the handle is turned parallel to the valve the flow is turned on. Ball valves are long lasting and even after years of obsoleteness are still able to achieve a flawless shutoff. Ball valves are the preferred choice for shutoff applications and at times are used for throttling applications as well although they do not offer the fine control that is normally desired for throttling applications.