Functionality: fully functional - the lenses of the lens and the viewfinder are clean, the viewfinder's visibility is good - without distortion, the focusing work is smooth and pleasant. Horizontal and vertical movements relative to the coordinate axes work smoothly and pleasantly.Refractive indexes checked - the contrast of the eyepiece when refracting light changes color.The thermometer is workable. Refractometer "RL 3" Laboratory refractometer RL 3 is designed (designed) to measure refractive index, average dispersion of liquids and solid and to determine (intent) the sugar content of percent in aqueous solutions. Due to the high accuracy achieved using even a few drops (drops) of liquid or substance (essence) when testing a refractometer, dimensions (measurements) represent a convenient and economic test method. They find their applications wherever the components of the mixtures show different refractive indices. Refractometric dimensions are used to research and manage jobs in the chemical and food industries. Technical details Scale Range Measurement: - Refractive index 1.3 - 1.7. - Sugar percentage by weight in aqueous% solution 0 - 85% Instrument Readings Accuracy: - Refractive index within the range 1.3 - 1.42 0.0004. - Refractive index within the range of 1.42 - 1.7 0.002. - Sugar percentage within the range of 0% -% 50% 0.2. - Sugar percentage within the range of 50% -% 85% 0-1 Scale Interval: - The refractive index is 0.001. - Sugar% percent 0.5 Refractometer constants: W = 61 41.0 ND = 1.75496 NF-NC = 0.02743 2k = 179.1901 '