Fangrui Product Details High Accuracy: These High-purity Buffer Powders Ensure Precise Ph Calibration With 0.01 Ph Accuracy At 2577 They Keep Your Ph Testers Sharp And Reliable For Consistent Results. 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 Ensure Freshness And Accuracy, Making Them Easy To Carry And Store. Quick Dissolution: These Pre-measured Ph Buffer Solution Powders Dissolve Quickly, Streamlining The Calibration Process; They Contain No Harmful Substances, Ensuring Safe Handling. 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 Youre Ready For Calibration. Colour:as Sh