Proper calibration of the instrument to sensor measuring system will ensure your results are accurate and repeatable. The use of standard calibration solutions is fundamental for correctly calibrating the measuring system. The Hanna range of conductivity calibration solutions has been produced to ensure the maximum accuracy for conductivity meters and probes. Guaranteed quality. Hanna conductivity meters can be calibrated in a few minutes right in the laboratory or field. For those users that require documented accuracy, conductivity (EC) solutions are available in bottles with certificates of analysis. Hanna solutions are offered in opaque, light-tight bottles that meet requirements. 1413 microsiemens/cm EC value at 25 degree C. 500mL size.