Milwaukee pH Startset is set of storage, cleaning and calibration solutions designed to extend the life of your pH electrode. Included in the kit is lab grade pH 4.01 buffer solution (MA9004), pH 7.01 buffer solution (MA9007), pH storage solution (MA9015) and pH cleaning solution (MA9016). All bottles are 230 ml. The buffer solutions certified to meet the standard to an accuracy of0.01 pH removing the inaccuracies involved with mixing buffers. The storage and cleaning solutions are lab grade produced with premium chemicals. Milwaukee solutions are designed to help you achieve reliable and repeatable pH measurements while extending the life of your electrode. Milwaukee pH Startset+ fundamental for the correct use of electrodes and for obtaining the most accurate and reproducible readings+ sealed against light with air tight, tamper proof cap+ marked with lot numbers and expiry datesIncluded:MA9004 pH 4.01 Calibration Buffer Solution (230 ml)MA9007 pH 7.01 Calibration Buffer Solution (