Digital Aid pH Calibration Solution Powder (4.00pH, 6.86pH, and 9.18pH). (1x3 Pack)(FBA) Make sure your pH Meter is Accurate! Measured exactly to ensure accuracy. Solution powders come pre-measured. Each of the packets makes 1 cup of pH buffer solution. Make pH solution without having to measure, Simply mix with 1 cup of distilled water for each packe 3 Year Shelf life. 3 Packets - 1 of each 4.00, 6.86, and 9.18 pH Powder. Money Back Guarantee if not Totally Satisfied. Click on the add to cart button NOW!