Thermo Scientific Orion® Fluoride Electrode with TISAB II 2 ppm as F-, 475mL. Thermo Scientific Orion® ISE calibration standards for use with ion selective electrodes from ammonia to water hardness. ISE calibration standards are used to calibrate ion selective electrodes. All standards are 1 pint (475mL) bottles, unless otherwise noted. Red liquid. Vinegar odor. Specific gravity: 1.02. pH: 5.0 to 5.5. Boiling point: 100°C. 475mL bottle/per each. Thermo Scientific Orion® #: 040907.