pH Buffer Calibration Solution 3-Pack: pH 4.00 Buffer, pH 7.00 Buffer, and Electrode Storage Solution — 250 mL (8.4 fl oz) Each — NIST Traceable Reference Standards for All pH Meters;

These buffer calibration solutions are suitable for the calibration of all pH meters. Each production lot is manufactured in our USA laboratory following carefully controlled written procedures and standardized against NIST standard reference materials (SRM) for highest accuracy. The finished product is assigned a unique Lot number and expiration date. These products will have greater than one year shelf life when received. The electrode storage solution will help keep the pH electrode clean and protected.