Features: Built-in ATC compensation Range (Automatic Temperature Compensation) from 10°C to 30°C For field use, without having to re-calibrate after changes in ambient working temperature. Soft rubber eye piece for comfortable viewing Equipped with scale measurement which provides direct reading Accurate testing results guaranteed Extremely easy-to-use and calibrate Made of premium material, durable in use Adjustable manual focusing Uses ambient light only which means battery or power source is not required. Cushioned with soft & comfortable non-slip rubber for easy use Manual calibration with mini-screw driver provided Specification: One SCALE: Brix scale: 0 to 28%Brix; Reference Temperature: 20°C ATC(Automatic Temperature Compensation) Compensation Range: 10°C~30°C (50°F~86°F) Weight: 246 g / 8.7 oz(approx.) Packing list: 1 x Refractometer 1 x Pipette 1 x Screw driver 1 x Cleaning cloth 1 x Instruction manual 1、Built-in ATC compensation Range (Automatic Temperature Compensation) from 10°C to 30°C 2、For field use, without having to re-calibrate after changes in ambient working temperature. 3、Soft rubber eye piece for comfortable viewing 4、Equipped with scale measurement which provides direct reading 5、Accurate testing results guaranteed