Built-in ATC Compensation: The Refractometer features an automatic temperature compensation range from 10°C to 30°C, making it suitable for on-site use without the need for recalibration after environmental temperature changes. Comfortable Viewing: Equipped with a soft rubber eyepiece, this refractometer ensures comfortable viewing while providing accurate readings through its calibrated measurements. Accurate and Reliable: With guaranteed precise testing results, this refractometer is extremely easy to use and calibrate, ensuring accuracy in every measurement. Long-lasting: Designed to be have a long lifespan, this refractometer is built to withstand regular use, ensuring its reliability over time. Convenient and Battery-free: The Refractometer only requires ambient light, eliminating the need for batteries or power sources. Additionally, it comes with a soft cushion made of comfortable and non-slip rubber, providing added convenience and stability during use.