Smart Digital Hygrometer Thermometer: The mini digital hygrometer has 3 symbols. A smiley face is displayed when the humidity is between 30% and 60%. It displays water droplets when the humidity is lower than 30% or higher than 60%, indicating dryness or humidity, so you can adjust your humidifier or dehumidifier accordingly and always live in a comfortable environment. Temperature control: -9.9°C ~ 50°C. Temperature measurement accuracy: ±1°C, temperature resolution: 0.1 (°C). °C/°F selection at the touch of a button, indoor thermometer measurement data updates every 10 seconds. Indoor hygrometer: 10% RH ~ 99% RH. Humidity Resolution: 1 (RH), Humidity Measurement Deviation Accuracy: ±5% RH. (The difference of 1°C/% RH between two thermometers may exist, but it is normal). \ Ultra-Portable: This thermometer-hygrometer (7.9 x 5.8 x 2.2 cm, weight 56 g) is small and light enough to be carried around without taking up too much space. The thermometer-hygrometer can be placed on a desk, mounted on the wall, or attached to a magnet, and its elegant design makes it a beautiful addition to any room. Wide range of applications: The mini digital LCD thermometer-hygrometer is popular and inexpensive. The thermometer/hygrometer is suitable for use in apartments, bathrooms, children's rooms, warehouses, basements, greenhouses, offices, farms, warehouses, etc. The thermometer operates on 2 x 3AAA-7 (Not included) and has a standby time of up to one year.