4 in 1: If you notice that the battery of your car, your solar plant or your heat pumps is no longer durable, do not hurry to change it. This antifreeze refractometer will help measure the specific gravity of your battery acid, then provide a quick reference of battery fluid condition. The refractometer can also be used to measure the freezing point of cleaning fluids, the freezing point, the ADBlue point. Easy to use: place 2-3 drops of sample on the prism of the refractometer , then look through the eyepiece to get the direct reading. ATC design: The refractometer adopts automatic temperature compensation from 10 to 30, direct reading, fast, accurate and lightweight. Contents: 1 refractometer, 1 calibration screwdriver, 1 pipette, 1 instruction manual, 1 cleaning cloth, and an included hard case that makes the refractometer convenient to store and carry. carry. Note: Do not measure abrasive or corrosive chemicals with this instrument.