Usage Tips:describe: With this refractometer you can easily check the quality of your grapes and make your wine better! The refractometer is mainly used to test the sugar content in the grape juice, and then determine the potential alcohol content of the wine in the fermented grape juice. Measuring range: Sugar content (mas Sacch): Sugar content (mas Sacch): 0-40%, alcohol content: 0-25, resolution 0.2%, alcohol content: 0.2% Easy to use: place 2 or 3 drops of sample on the main prism, close the plate and read the Brix value through the observation window; Calibration: 20C water zero, automatic temperature compensation (ATC) between 10C and 30C Accurate measurement: clear dividing lines (blue and white), good readability (identifiable under sunlight), eyepieces with adjustable sharpness Calibration: 20 distilled water zero calibration, 10 to 30 automatic temperature compensation (ATC) Package contents: 1 piece refractometer