Set of premium quality pH 4.01 and 7.01 calibration buffer solutions from HANNA. Each sachet has the lot number and expiration date stamped on it and is made of light block foil ensuring freshness each time one is opened. The HANNA Calibration Set consits of 5 sachets of pH 4.01 and 5 sachets of pH 7.01 with each containing 20 mL of buffer solution.HANNA Calibration Buffer Set pH 4.01 + 7.01+ 5x buffer pH 4.01 and 5x buffer pH 7.01+ color coded label for easy pH buffer value identification+ accuracy of +/- 0.01 pH at 25C+ temperature chart of the actual pH value at various temperatures printed on each sachet