Refractometer, also known as refractor is able to measure the transparent, translucent liquid or solid refractive index nD and average dispersion nF-nC instrument (which measured mainly transparent liquid). If the instrument is connected to the thermostat, you can determine the temperature within the refractive index of 0 ~ 70 ND. Refractive index and average dispersion is one of the important optical constants of matter, which can be used to understand the optical properties of materials, purity, concentration and dispersion size. The instrument can also measure the percentage of sugar content in sucrose solution concentration. Therefore, this kind of instrument has a wide range of applications. It is one of the common equipment indispensable to the factories and research institutes in the petroleum industry, oil industry, paint industry, food industry, daily chemical industry, sugar industry and geological survey.