Feature: 1. ATC FUNCTION: Brine refractometer with automatic temperature compensation minimizes the effect of temperature on accuracy, allowing you to obtain accurate results. 2. DUAL SCALE: The seawater refractometer has a dual scale specific gravity, allowing you to obtain results in two different units with a single test. 3. EASY TO USE: After calibration, place 2-3 drops of sample solution on the prism, facing the light, and then you can get an accurate reading through the optical eyepiece. 4. DURABLE MATERIALS: The brine refractometer is made of aluminum and ABS rubber, which is rust proof, non staining, wear resistant and durable. 5. BROAD USE: The salinity refractometer is designed to measure the salinity of water and brine and is ideal for aquariums, marine monitoring, agriculture, fish farming, and brackish pools. Specification: Item Type: Salinity Refractometer Material: Aluminum alloy, ABS, rubber Measurement Range: 0-100% Grid Value: 1% Accuracy: ±1%. Package List: 1 x Salinity Refractometer 1 x Dropper1 x Screwdriver1 x Soft Cloth1 x Instruction1 x Storage Box Note: This instrument is a accuracy optical instrument, in the use and maintenance should pay attention to the following matters: 1. In the use must be careful and cautious, strictly according to the instructions, not arbitrarily loose the connection parts of the instrument, not to fall, collision, and forbidden to occur violent vibration.2. After use, it is strictly forbidden to wash directly into the water, should be wiped with a clean soft cloth, for the optical surface, should not touch, scratch. 3.3. The instrument should be put in a dry, non corrosive gas place for storage.4. Avoid losing spare parts.