1. 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 determined2. MEASURING RANGE: ethanediol (ethylene glycol): -500C to 0C; Propanediol (propylene glycol): -500 C to 0 C; Windscreen water - ethanol + water: -40 C to 0 C, propylene glycol + water SRF1): -40 C to 0 C. Urea concentration 30% - 35%, battery acid from 1.10 to 1.40 kg / L.3. TEMPERATURE COMPENSATION: Temperature compensation device included to ensure that the measurement is easy and convenient to PRECISION MEASUREMENT: Adjust the eyepiece group optical system: 4-8 times the amplification system, stepless manual focus. Can adapt to all eyes.4. HIGH QUALITY: 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.