This is a calibration solution used to check the accuracy of and calibrate conductivity meters and probes.Its primary purpose is to provide a reliable, known electrical conductivity (EC) value. When a conductivity probe is placed in this solution, the meter should display a reading of 1.408 mS/cm (or 1408 µS/cm) at a standard temperature, typically 25°C.If the meter's reading is different, it needs to be adjusted (calibrated) until it matches this standard value.