Hand Held Brix/Salt Refractometer with ATC for brine fruit Beer, Dual Scale(2 in 1 Brix 0-32%, Salt 0-28%) Instructions: ATC accuracy: Hand held brewing refractometer with automatic temperature Compensation (ATC), the brix refractometer will account for changes in ambient temperature and automatically compensate accordingly to provide accurate and repeatable measurements on an easy to read scale. Dual scale - Bix 0~32% specific gravity 0.2% .Measurement range of Salinity 0~28%, specific gravity 0.2% . 1.ATC: Built-in automatic temperature compensation 2. Dual design: Rapidly and precisely display the Bix( 0~32%) ,specific gravity (0.2%) .Measurement range of Salinity (0~28%), specific gravity (0.2%) at the same time, without switching units! Easy to use: Simply test a drop of your brew on the prism and hold the refractometer to the light, then look through the eyepiece to get the reading, no need for clutter some tables! Operation steps: 1. Open the cover with a soft cloth carefully wipe detection prism. 2. Test a few drops of the solution, placed on the detection prism, gently close the cover ,to avoid air bubbles, spreading the solution acro the surface of the prism. 3. Align the light source and observe through the eyepiece, adjusting with the wheel. 4. Make a clear p> Calibration Method:(Details please check below photos) Accurate measurement depends on careful calibration.To calibrate the refractometer accurately.First you should make sure the ambient temperature i about 68F,I recommend you do the calibration in an air conditioned room in which the temperature is set on 68F. Distilled water to calibrate Open the cover plate,place 2-3 drops of distilled water on the prism,then close the cover plate and make sure the water spreads acro the prism without air bubbles or dry spots.Waiting for about 30 seconds to let the reading to stabilize,look into the eyepiece and turn the calibration screw with the screw driver until the reading is 0. Packing list: 1*Refractometer 1*Clean Cloth 1*Screwdriver 1*Dropper 1*Instruction manual