Glycol antifreeze freezing point: -50 to 0°C, division value of 1°C Freezing point of the propylene glycol antifreeze: -50 to 0°C, division value of 1°C Specific gravity of the electrolyte: 1.10–1.40, index value 0.01 (1.15–1.20 requires charging; 1.20–1.25 indicates sufficient charge; 1.25–1.30 indicates full charge) Glass cleaning fluid freezing point: -40 to 0°C, division value of 5°C Includes: 1 x Refractometer 1 x Screwdriver 1 x Manual 1 x Cleaning cloth 1. USE: This refractometer allows you to determine the ethylene glycol and propylene glycol concentration in antifreeze used in vehicles, solar systems, heat pumps, heating systems, and other machinery. It also measures 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 measurements across varying ambient temperatures. PRECISION OPTICS: Features a 4x to 8x magnification system with continuous manual focus adjustment. Designed to accommodate individual eyesight differences. 4. HIGH QUALITY: Durable chrome-plated brass body provides excellent resistance to chemical corrosion and wear, significantly extending the lifespan compared to refractometers with aluminum housings.