Product Description: Freezing point range for ethylene glycol antifreeze: -50°C to 0°C, with a scale division of 1°C Freezing point range for propylene glycol antifreeze: -50°C to 0°C, with a scale division of 1°C Specific gravity of electrolyte: 1.10–1.40, with a scale division of 0.01 (1.15–1.20 indicates need for charging; 1.20–1.25 indicates sufficient charge; 1.25–1.30 indicates full charge) Freezing point range for glass cleaning fluid: -40°C to 0°C, with a scale division of 5°C Package Includes: 1 x Refractometer 1 x Screwdriver 1 x User Manual 1 x Cleaning Cloth 1. USE: This refractometer allows you to measure the concentration of ethylene glycol and propylene glycol in antifreeze used in vehicles, solar systems, heat pumps, heating systems, and other machinery. It can also determine the freezing point of windshield washer fluid and battery electrolyte. 2. MEASURING RANGE: - Ethylene glycol (ethanediol): -50°C to 0°C - Propylene glycol (propanediol): -50°C to 0°C - Windshield washer fluid (ethanol + water): -40°C to 0°C - Propylene glycol + water (SRF1): -40°C to 0°C - Urea concentration: 30% to 35% - Battery acid specific gravity: 1.10 to 1.40 kg/L 3. TEMPERATURE COMPENSATION: Built-in automatic temperature compensation ensures accurate and reliable readings under varying temperature conditions. PRECISION OPTICS: Features an adjustable eyepiece with 4x to 8x magnification and stepless manual focus, suitable for all users. 4. HIGH QUALITY CONSTRUCTION: Durable chrome-plated brass body provides excellent resistance to chemical corrosion and wear, significantly extending the service life compared to refractometers with aluminum housings.