Pocket refractometers are very commonly used which can be used for low, middle, and high resolution Brix concentration. The low range can be used for high-precision measurement such as fruit juice, cola and most kinds of beverage. The middle range can be used for concentrated fruit juice, canned food, sugar solution detections, sauce, ketch up, seasoning and many kinds of industry fluids. The high range can be used for use with food products of high sugar content such as liquid sugar, honey, etc. They can be used for industry fluid testing, such as for vegetable oils, industry, and many other chemical liquids or laboratory use fluids. It provides a fast and accurate way to test the ratio and concentration in water soluble cutting oil and many other industries fluid.