1. The antifreeze freezing point detector, methanol refractometer, and battery water densitometer, a portable dual - purpose refractometer for measuring antifreeze freezing point and battery fluid density, is an optical instrument designed based on the corresponding relationship between the solution concentration (freezing point respectively) and the refractive index. 2. This instrument can quickly test the freezing points of ethylene glycol and propylene glycol antifreeze crystals, measure the specific gravity (relative density) of battery water, and can also be used for automotive cooling water, coolant antifreeze, etc. The antifreeze freezing point determination refractometer is used to measure the freezing point temperatures of cooling systems, ethylene glycol and propylene glycol - type automotive coolants, and water - based window cleaning fluids. It can also check the specific gravity of the battery and the usage of the electrolyte. 3. The refractometer is made of high - quality materials and has a metal body. The body perfectly showcases the metal material, with a good tactile surface texture, uniform grain, a strong finished - product structure, and a long service life. Zero - point calibration: Calibrate with distilled water at 20°C in a 20°C environment. This product is mainly used to measure the freezing point of glass aqueous solutions. Due to its reliable principle, accuracy meeting practical requirements, small size, light weight, and beautiful appearance, it is widely used in the automotive industry. 4. Urea: 30%, 35%. The freezing point of EG antifreeze is - 50~0 (ethylene glycol). The freezing point of PG antifreeze is - 50~0 (propylene glycol). The freezing point of chemical cleaning agents is - 40~0 (inclusive). Quantity shipped: 1 piece. Thank you for purchasing products from our high - quality store. Have a great day!