A ball valve is a kind of shut of valve that controls the flow via a rotary ball with a hollow core. When the hollow core is parallel to the water inlet, the fluids can flow freely. However, when the ball valve is turned 90o the fluid is blocked. They can stop the flow of fluid without a pressure drop and provides a watertight seal. Because of their durability and reliability they are a popular choice for use in both residential and commercial settings for water, natural gas and chemical applications. They are also ideal for emergency applications due to their speed.