Hanna Instruments pH 6.86 Calibration Solution 500mL HI7006LColor coded label for easy pH buffer value identification Accuracy of + 0. 01 pH @ 25C Temperature chart of the actual pH value at various temperatures printed on each bottle premium quality pH 6. 86 calibration solution. Hanna calibration buffers have the lot number and expiration date clearly marked on the label and are air tight with a tamper proof seal to ensure the quality of the solution. Hannas line of calibration buffers have been specially