Feature:   It has a refractometer with automatic temperature compensation to give you the most accurate measurement in any type of environment temperature. (ATC: 10~30°C)       Specifications:  Adblue: 30%-35% Propylene glycol: between - 50 and 0 ℃ Glycol: 50-0 ℃ Detergent: between -40 and 0 ℃ Battery liquid: 1.10-1.40 SG Size:159mm*23mm*23mm        Use and Calibration:  Use and calibration: A .Preparation before use: With the prism facing the light source, adjust the focus tube of the eyepiece until the scale line is clear. B.Calibration: 1.Open the daylight plate .and place 1-2 drops of standard solution.on the prism .and light press the daylight plate 2. till get a lights and darks boundary. turn the calibration screw 3. make the lights and darks boundary line of the field of view of eyepiece and datum line are coincide. (0%) Note: 1. Calibration and adjustment have been completed before leaving the factory, you can use it directly. 2. Before the test, the standard solution (pure water) instrument and sample must be at the same temperature to get accurate results. C.Use: 1. Open the solar panel, clean the surface of the prism with flannel, drop 1-2 drops of the sample on the prism, close the solar panel e2, lightly press, and read the relative scale of the light and dark borders, which is the composition of the sample. 2. After the measurement is completed, directly wipe the scale and the surface of the solar panel with a wet flannel. After drying, please keep it safe      Packing List:  1 x Refractometer 1 x dropper 1 x screwdriver 1 x wipe clean (1) 1 x Lint. 1 x manual (English, Russian, Spanish, German, Japanese, Korean) 1 x carton