pH 4.01 buffer solution (20 mL)
Solution to calibrate electronic pH-meters (calibration value pH 4.01)
pH ± 0.01 @ 25 °C/77 °F
Single dose packet of 20 mL ready for use. To calibrate pocket-size pH-meters, with or without probe, directly insert the probe into the packet, making sure that the probe is covered at least 4 cm into the liquid. The content of the packet is very practical, because the solution is always "fresh" and protected from light, to the advantage of a very accurate calibration.