Aprea Instruments AI1116 pH calibration buffer solution Kit includes three 16oz bottles of pH buffer solutions (pH 4. 00, pH 7. 00, and pH 10. 01), plus one piece of Apera CalPod Solution Holder, which helps users organize all the solutions in one place and streamline the entire calibration process. The color-coded buffer solutions are standardized against NIST certified pH References within 0. 01 pH at 25˚C (77˚F), which is ideal for the calibration of all pH meters that use USA standard buffers for calibration. Since pH level is affected by temperature, a temperature/pH reference Chart is provided on the bottle Label for reference. Keeping the standard solutions fresh and uncontaminated is the precondition for accurate pH measurement. Pour 2-3 oz. of solution into a clean container for calibration. If sealed well, the same amount of pH solution poured out can be used for 10-15 times before replacement (10. 01 up tp 5 times). Never pour the used solution back to the original bottle to avoid contamination. The expiration date is printed on the bottle. MSDS documents are downloadable. COA can be achieved per request. Note: Store at room temperature and away from direct sunlight. Keep the bottle tightly closed when not in use. Keep out of reach of children. All the solutions are double-sealed, not subject to the dot shipping restrictions, and have a 2-year shelf life.