No batteries required: this weather station is analog so it works without batteries! Robust and design: made of stainless steel, this GardenMate weather station is robust and simple. Its traditional black and white dial gives you all the information you need at a glance! Versatile: The weather station consists of a 960-1060 hPa barometer, a -20C to 50C thermometer and a 20 to 98% RH hygrometer. Size: diameter 14cm, height 4cm, weight 180g. Tips for testing thermometers: 1. Watch the temperature change: Place it in an environment with a large temperature difference from the ambient temperature for a period of time, and there will be obvious changes in the thermometer needle. For example: put it in the refrigerator, because the mechanical movement changes slowly, it takes longer to change slowly. 2. Watch the humidity change: You can take a deep breath at the place with a hole at the bottom of the back of the product, and you will clearly see the upward change of the humidity pointer, and the pointer will fall back after a moment. Thermometers that meet the above two points are normal products. Please use it with confidence! Thank you 3. Watch the air pressure changes: Due to the different air pressures in different places, the pointer display positions are different, and some areas may also encounter the situation where the pointer with very low air pressure is deviated to the lower range and exceeds the range. Atmospheric pressure changes more slowly. Typically, the change will be evident when the weather changes from sunny to rainy or from rainy to sunny. Therefore, if you don't see the air pressure needle moving, please turn the comparison pointer to the same position as the air pressure pointer, then be patient. Just wait a few days.