... easy to clean 3,Simple structure Free chlorine (constant-voltage electrode) Application Suitable for the residual chlorine in water industry and filing ... , easy to clean . Suitable for the residual chlorine in the water ,chlorine dioxide ,ozone measurements .·Technical parameterMeasurement range:0~2ppm, ... 20°C(Max.)Electrode size :Diameter 12mm ,length 110mm Free chlorine (constant-voltage electrode)