Be confident in your purchase we're an Authorized Milwaukee Dealer. How cool is that?!?!? Features: pH 10.01 Calibration Buffer Solution - 20 mL (box of 25) Fundamental for the correct use of electrodes and for obtaining the most accurate and reproducible readings Sealed against light and air Ideal for on-the-spot calibration Simply open, insert the tester or electrode into the sachet and calibrate Formulated with a 5 year expiry Color coded for easy identification Specs: Accuracy Standard: 0.01 pH Value: 10.01 pH @25C Sachet Size: 20 mL Quantity: 25 Certificate of Analysis: No Probe calibration is a simple procedure for optimal performance and should be done any time your readings become suspect. Calibration should be performed at least once a month. M10010B is a lab grade pH 10.01 calibration solution certified to meet the standard to an accuracy of 0.01 pH removing the inaccuracies involved with mixing from powder. Sachet packaging means that you get fresh solution every time. Ideal for infrequent or field use. No risk of using an expired or contaminated solution. Milwaukee solutions are designed to help you achieve reliable and repeatable pH measurements while extending the life of your electrode.