Bluelab® conductivity standard solutions are essential for use with all Bluelab® products. Bluelab® Solutions are manufactured specifically for Bluelab® products and are referenced to high laboratory standards to ensure your products last longer and maintain accuracy. The 2.77EC solution is used as a reference or checking solution to ensure you have adequately cleaned the EC/ppm probe. Calibration solution should be stored in a cool place out of direct sun and heat. Please keep out of reach of children and store with lid securely tightened.