High Accuracy: These high-purity buffer powders precise pH calibration with ±0.01 pH accuracy at 25℃/77℉; They keep your pH testers and reliable for consistent results. Quick Dissolution: These pre-measured pH buffer solution powders dissolve quickly, streamlining the calibration process; They contain no harmful substances, ensuring safe handling. High Stability: These premium buffer powders maintain accurate pH values of 6.86, 4.00, and 9.18, even after long-term storage, saving you from repeated purchases for pH calibration. Individual Packets: Includes 6 packets of pH 4.00 solution powder, 6 packets of pH 6.86 solution powder, and 6 packets of pH 9.18 solution powder; Each packet is individually sealed to freshness and accuracy, making them easy to carry and store. Simple to Use: Compatible with any pH tester and probe; Just empty a packet into a clean glass beaker, add 250ml deionized or distilled water, stir gently until dissolved, and you're ready for calibration., Manufacturer: Ounfhtrttk