A plug valve with class 150 & 300 flanged ends is a type of quarter-turn valve that uses a cylindrical or conical plug to control fluid flow through a pipeline. The plug has a through hole that lines up with the pipeline when the valve is open, allowing fluid to flow through. When the valve is turned a quarter of a turn, the plug is rotated to block the fluid flow.

Plug valves are often used in applications where the valve needs to be quickly and easily operated and requires a tight shut-off. They are commonly used in the oil and gas industry, as well as in chemical and petrochemical plants, water treatment plants, and other industrial applications. Plug valves can be made of various materials, including metal, plastic, and ceramic, depending on the specific application and the fluid being handled.