This refractometer is used to measure the sugar content in the original grape juice, then the alcohol content in the wine (to be made from the grape juice) can be known from the scale, and the grapes juice can be fermented by measuring the alcohol content (by volume) of the wine juice Measuring Range - Brix: 0-40 percent , Alcohol: 0-25 percent Easy to Use - Place 2, 3 drops of the sample on the main prism, close the plate and look through the viewing window to read the Brix value Calibration - Zero calibration with water at 20 C, automatic temperature compensation 0-30 C (ATC) Package - Refractometer, A hard plastic case, Mini screwdriver, 1x Pipette, Instruction manual. This Refractometer is mainly to measure the sugar content of the grape juice, so as to predict the alcohol content of the wine to be produced. Because the alcohol content of wine is positively related to the sugar content of grape juice, of course, if you use it as a sugar content meter, it is also possible It is designed based on the principle that liquids of different concentrations have different refractive indices. It has the advantages of speed, accuracy, light weight and small volume. Usage: Open the cover and carefully inspect the prism with a soft cloth. Take a few drops of the solution to be measured and place it on the detection prism. Then gently close the cover to avoid air bubbles and spread the solution over the entire prism surface. Aim the light entrance plate of the instrument at the light source or a bright place, observe the field of view through the eyepiece, and turn the eyepiece to adjust the handwheel to make the blue and white border of the field of view clear. The scale of the dividing line is the concentration of the solution. Calibration and Temperature Calibration: The instrument needs to be calibrated to zero before measurement. Take a few drops of distilled water and place it on the detection prism. Turn the zero adjustment screw to adjust the scale to 0 percent of the scale. The detection prism is then wiped and tested. Another method (only for determining the sugar content) is to use a temperature correction table and then add (or subtract) the temperature correction value to the value read at ambient temperature to get an accurate value. (The manual includes a temperature correction table for sugar readings.) Package: 1 x Refractometer, 1 x A hard plastic case, 1 x Mini screwdriver, 1 x Pipette, 1 x Instruction manual Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.