ATC function (automatic temperature compensation) provides accurate pH readings across a range of solution temperatures, reducing the need for manual adjustment. Automatic calibration simplifies setup and ensures reliable, repeatable results with minimal effort. IP65 fully waterproof design protects the device from dust and water jets, suitable for use in wet environments and outdoor testing. Replaceable pH sensor probe with an inserttype design enables convenient and fast replacement, extending the device's lifespan without specialized tools. Pocketsize and portable with switchable backlight and a large LCD display for clear reading in any lighting conditions. Data hold function allows you to freeze the reading for documentation or sharing without rushing the measurement. Use scenarios Aquariums and ponds: monitor pH and temperature of tank or pond water to maintain a healthy aquatic environment and adjust conditions as needed. Hydroponics and gardening: keep nutrient solution pH within optimum ranges to improve nutrient availability and plant health, while easily reading temperature. Field testing and pool/spa maintenance: test pH and water temperature of outdoor water sources, swimming pools, or spa water, with the ability to hold readings for recordkeeping.