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: 1.101.40, index value 0.01 (1.15 ~ 1.20 needs charging; 1.20 ~ 1.25 sufficient charge; 1.25 ~ 1.30 sufficient charge) Glass cleaning fluid freezing point: -40 ~ 0 C, division value of 5 C Contains: 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 can also measure the freezing point of windshield washer fluid. 2. MEASURING RANGE: Ethylene glycol: -50C to 0C; Propylene glycol: -50C to 0C; Windshield washer fluid (ethanol + water): -40C to 0C; Propylene glycol + water (SRF1): -40C to 0C; Urea concentration: 30%35%; Battery acid: 1.10 to 1.40 kg/L 3. TEMPERATURE COMPENSATION: Built-in automatic temperature compensation ensures accurate and reliable measurements. Optical system with 48x magnification and stepless manual focus adjustment. Suitable for all users. 4. HIGH QUALITY: Chrome-plated brass body provides excellent resistance to chemical corrosion and wear, significantly extending the lifespan compared to aluminum housings.