Feature: 1. More accurate measurement, the resolution of the digital salt concentration meter is 0.01%. 2. This digital refractometer is easy to use and easy to calibrate, only 1 drop of sample is needed, can easily test TDS/Brix. 3. Adopts linear CMOS sensor with high precision, light in weight and easy to carry. 4. Large LCD display for easy reading and the protective cover prevents dust from entering the prism column. 5. IP65 waterproof with shockproof material, low power consumption and 10-50℃ automatic temperature compensation. Specification: Condition: 100% Brand New Item Type: Digital Refractometer Material: Plastic Waterproof: IP65 Temperature Compensation: 10-50℃ Automatic Temperature Compensation Battery: 1 x 1.5V AAA Battery (Not Included) Model Function Measurement Number Measurement Range Resolution Accuracy DR201 Salinity S01 0.0-28.0% 0.10% ±0.2% Salinity S02 0-280‰ 1‰ ±2‰ Specific Gravity S03 1.000-1.217 0.001 ±0.002 Refractive Index S04 1.3330-1.3900nD 0.0001nD ±0.0003nD Package List: 1 x Digital Refractometer (Battery Not Included) 1 x Instruction Manual 1 x Suction Cup 1 x Plastic Dropper