Online conductivity sensors are designed for measuring conductivity in ultra-pure water and water treatment applications. Ideal for power plants and water treatment industries, these sensors have a durable double-cylinder structure made from titanium alloy, which forms a chemical passivation when oxidized. The conductive surface can resist most liquids except hydrofluoric acid. The sensor accommodates various temperature compensation components and is resistant to strong acids and bases, making it suitable for industries like sewage treatment and seawater purification.