A ball valve is a type of valve that controls the flow of liquids or gases through a pipe. It consists of a spherical disc, or ball, with a hole in the center. When the ball is rotated, the hole aligns with the pipe, allowing flow, or it blocks the flow when turned perpendicular. Ball valves are known for their durability and ability to provide a tight seal. These valves are commonly used in various applications, including plumbing, oil and gas, and water treatment. They are favored for their quick operation and reliability, making them suitable for both on-off and throttling services.