Plug valves are a quarter-turn, shut-off valve that quickly stops and starts media flow. The valve's plug provides fast-closing action and a large sealing surface to prevent leak paths. Ground plug valves are used in low-pressure applications and are typically connected to air and water lines. Instrumentation plug valves are compact, rated for high-pressure applications, and used in control and measurement systems. LP and natural gas plug valves meet industry standards for use with liquefied petroleum and natural gas. Industrial process plug valves have housings constructed of cast iron, a vibration-, impact-, heat-, and abrasion-resistant metal and are suited to applications moving slurries or liquids with suspended solids. High-purity plug valves have a body and stem consisting of PFA (polyfluoroalkoxy alkanes), an impact- and corrosion-resistant polymer, for applications with strict hygiene requirements, such as semiconductor manufacturing.