Ethylene Glycol: -50C to 0C (0%–70%) Propylene Glycol: -50C to 0C (0%–70%) Resolution: 5C, 5% (ATC) Temperature Compensation Range: 10C–30C Field of View Intermediate Scale: (ETHYLENE GLYCOL) Ethylene glycol antifreeze freezing point (PROPYLENE GLYCOL) Propylene glycol type antifreeze freezing point Left Scale: (BATTERY FLUID) Battery liquid specific gravity 1.15–1.20 to be charged 1.20–1.25 power enough 1.25–1.30 sufficient power Right Scale: Glass cleaning solution freezing point Principle: The instrument measures the freezing point of antifreeze and glass cleaning agent, as well as the specific gravity of lead-acid battery electrolyte. It includes a temperature compensation device to ensure simple, convenient operation and accurate measurement within an ambient temperature range of 10C to 30C. The device operates on the principle of the critical angle of total reflection to measure the refractive index of the solution, which is then calibrated to determine the concentration and performance of the liquid. Due to its reliable principle and accuracy, it meets practical requirements and is widely used in the automotive industry. Usage Notes: 1. Avoid long-term placement in environments with relative humidity above 85% to prevent damage to the optical system. 2. Do not allow liquid or water to enter the adjustment knob or eyepiece to avoid damaging internal components. 3. Avoid dropping or impacting the instrument to maintain measurement accuracy. 4. After use, immediately wipe the prism and refractive plate clean with a soft cloth. Package Includes: 1 x Refractometer 1 x Pipette 1 x Instruction Manual 1 x Mini Screwdriver 1 x Cleaning Cloth