Battery-free mechanical operation for reliable performance - The wall thermometer and hygrometer is mechanical and designed for a long service life. There are no batteries to discharge in cold weather and no replacements needed. The analogue mechanism operates without power. Simple to read at a glance - Read both current temperature and humidity without instructions or buttons. This is the easiest thermometer to operate, with at-a-glance information. 2-in-1 design for temperature and humidity - Hygrometer displays humidity, while the thermometer measures temperature from -20°F to 120°F (-30°C to 50°C). Humidity ranges from 1% to 99%, suitable for a wide range of indoor climates. Designed for wall mounting and reliable indoor use - A practical 2-in-1 instrument that stays accurate and unobtrusive for everyday indoor monitoring in homes, offices, kitchens, nurseries, or other living spaces. Use scenarios - In the kitchen or living area to monitor moisture and temperature and maintain comfortable conditions. - In a nursery or child’s bedroom to help create a conducive sleep environment. - In a greenhouse, terrarium, or plant area to track climate and support healthy indoor plants.