Accurate With built-in MEMS sensor, provides high precise monitoring. Temperature range: -20-60(-4-140) Humidity range: 0-99%RH. The temperature is accurate to 0.5(1), while humidity is 5%RH. App Control & Smart Alert Data on the APP shows red when data is beyond preset range, and the alert will be sent to APP. Intelligent function enables you to adjust situation of your wine cellar, greenhouse or other places in time. Support Android 4.3 or above, iPhone 4s or above. Bluetooth Wireless Connectivity Use Bluetooth 5.0 chip. Easily monitor temperature and humidity data on Sensor Blue App (free downloading from App Store or Google Play) via Bluetooth. Data Storage Export Every 10 mins and total up to 100 days of data is stored internally in the device. Available to download data in CSV format for free after registered account. ApplicationUpgraded Battery - CR2477. The battery lifespan is about one year. Perfect for monitoring home, pets, refrigerators, freezers, walk-in cooler, wine cellars, greenhouses and musical instruments.