The HI 96831 Ethylene Glycol Digital Refractometers is rugged, portable, water resistant devices that utilize the measurement of refractive index to determine the percent volume and freezing point of ethylene glycol based solutions. HI 96831 sample is measured after a simple user calibration with distilled or deionized water. Within seconds, the refractive index and temperature are measured and converted into one of two measurement units; % Volume or Freezing Point. These instruments utilize internationally recognized references for unit conversion and temperature compensation for glycol solutions (e.g. CRC Handbook of Chemistry and Physics, 87th Edition).