1. Built-in ATC (automatic temperature compensation) from 10 to 30 degrees Celsius.2. Soft rubber eyepiece for comfortable viewing3. Equipped with scale measurement, can be directly read to ensure accurate test results4. Rugged and durable, long service life, adjustable manual focus5. Use only ambient light, which means no battery or power supplySimple and easy to use.6. Place a few drops of liquid on the optical parts of the refractometer, cover the prism (liquid will be easier to spread on the prism), observe the light through the eyepiece (focus if necessary), and you will be able to read the resulting value on the scale.7. Measuring range 0-80% v / v (VOL- alcohol volume percentage)8. Widely used in scientific research, food production, alcohol retail, etc.9. Reference temperature 20 ° C10. Packing list:1 x wine meter1 x plastic pipette1 mini screwdriver1 x cleaning cloth1 x manual