Available In 220Ml Bottles And 20Ml Sachets. Traditional Buffer Solutions Are Packed In 220Ml Leak-Proof Bottles And Are Recommended For Lab Application. Sachets Are Sealed Against Light And Air And Are Ideal For On-The-Spot Calibration. Simply Open, Insert The Tester Or Electrode Into The Sachet And Calibrate. Sachets Are Sold In Boxes Of 25 Pieces.