The "Pocket" coolant refractometer PAL-91S, easily measure the coolant in brine and other agents of Ethylene Glycol. Measured value displayed digitally. The freezing point of the sample can also be measured and displayed.Antifreezing solution (coolant) whose main ingredient is ethylene glycol is widely used as mixed in cooling water of car's radiator, as cooling medium for central air - conditioning system, freezer / refrigerator, cooling coil, cooling fixture, and so on. The higher the concentration is, the lower the temperature at which ethylene glycol is frozen is. Therefore, it is needed to adjust freezing temperature of antifreezing solution so that it dose not freeze under a specific operation temperature.