Usage Tips:Product Description: Glycol antifreeze freezing point: -50 ~ 0 °C, division value of 1 °C. Freezing point of the propylene glycol antifreeze: -50 ~ 0 °C, division value of 1 °C. Specific weight of the electrolyte: 1.10-1.40, index value 0.01. Glass cleaning fluid freezing point: -40 ~ 0 °C, division value of 5 °C. Includes: 1 x refractometer 1 x screwdriver 1 x manual 1 x cleaning cloth Use: With this refractometer, the ethylene glycol and propylene glycol concentration of the antifreeze in your car, your solar system, heat pumps, the freezing point of windshield washer fluid, heating system, or other machines or systems can be determined. Measuring range: Ethylene glycol: -50°C to 0°C Propylene glycol: -50°C to 0°C Windscreen washer fluid - ethanol + water: -40°C to 0°C Propylene glycol + water: -40°C to 0°C Urea concentration: 30% - 35% Battery acid: 1.10 to 1.40 kg/L Temperature compensation: Temperature compensation device included to ensure that the measurement is easy and convenient. Precision measurement: Adjust the eyepiece group optical system: 4-8 times the amplification system, stepless manual focus. Can adapt to all eyes. : Our chrome-plated brass body is resistant to chemical corrosion and wear-resistant, the lifespan of the refractometer is increased several times than other aluminum housings.