The Extech CL200 Waterproof Total Residual Chlorine Tester is a robust and waterproof (IP67) measuring stick. The high accuracy and the replaceable measuring electrode is distinguished from the compact device.The CL200 is a revolutionary first of its kind measurement device that offers direct reading of Total Chlorine from 0.01 to 10.00 ppm. In addition to the numerical display of the measurement these units have a bar graph display and a measurement memory. For this type of electrode method, a reagent tablet must be added to the measurement solution before testing. The advantages of the CL200 to the user include: Easy to use and maintain, high accuracy, self-calibration, and fast response. The CL200 offers simultaneous Chlorine and Temperature displays and a 15-reading memory storage. Careful use and maintenance will provide years of reliable service.The CL200 can be used wherever a measurement of the total chlorine in water is needed. This is also referred to as total residual chlorine. It measures the total of all chlorine present in all forms, including dissolved free chlorine, chloramines, hyporchlorous acid and hypochlorite ion. Typical applications include measurements of discharge water from water treatment plants, public drinking water supplies and cooling towers, and measurement of disinfectant properties in swimming pools and cooling water applications.