The QSC kit consists of three precision DIN buffers (pH 4.01, pH 6.87 and pH 9.18 with a deviation of +/- 0.01 pH at 25° C respectively) an initial calibration can be performed in glass vials for IDS pH electrodes. Ideal for quality control: All subsequent calibrations are compared to this calibration and thus deliver exactly the current status of the sensor with respect to its initial values.