The Classical quick open 90 degree angle stop cock valve, also known as a quarter turn valve or ball valve, is a type of valve commonly used to regulate the flow of liquids and gases in plumbing systems. Unlike other types of valves that require multiple turns to open or close, the Classical quick open valve can be turned just a quarter of a full rotation to control the flow of fluid.

The valve consists of a hollow sphere with a hole in the middle, called a ball, that rotates on an axis perpendicular to the direction of flow. The ball is positioned between two seats, which are the sealing surfaces where the ball seals against when the valve is closed. The valve is operated by a lever or handle that rotates the ball to either allow or block the flow of fluid.

One of the main advantages of the Classical quick open valve is its ability to quickly and easily shut off the flow of fluid. With just a quarter turn of the handle, the valve can be completely closed, preventing the flow of fluid in the system. This makes the valve ideal for emergency shut-off situations, as well as for applications where precise control of fluid flow is required.

Another advantage of the Classical quick open valve is its durability and resistance to wear and tear. The valve is typically made of materials such as brass, stainless steel, or PVC, which are known for their strength and resistance to corrosion. The ball and seats of the valve are also typically made of hard materials such as ceramic or metal, which can withstand the constant wear and tear that occurs during normal operation of the valve.