The Apera Instruments 12. 88 mS/cm Standard Conductivity Calibration Solution is made of high-purity chemicals, standardized against NIST certified references at 25°C (77°F). It's ideal for the calibration of all types of conductivity meters. Since conductivity value is affected by temperature, the temperature & conductivity reference table is provided on the bottle label. All the solutions are double-sealed, not subject to the DOT shipping restrictions, and have a 1-year shelf life. The expiration date is printed on the bottle. MSDS is downloadable at support. aperainst ; The Certificate of Analysis can be acquired by requests. 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.