Wireless App ControlWe uses a high-end Bluetooth 5.0 chip and can easily monitor temperature and humidity data on app via Bluetooth. (Free downloading from App Store and Google Play)   Higher Accurate MonitorUsing an accurate and sensitive Sensirion temperature and humidity sensor, it can achieve a temperature error of ± 0.5 ° C (± 1 ° F), a humidity error of ± 3%, and refresh once per second for higher accuracy.   Data Storage ExportSupport temperature data export function, record a group of data every 10 seconds, can store up to 100 days of data. Data on the APP shows red when data is beyond preset range.   Portable DesignWireless sensors Smaller size than other brands (1.5 x 1.5 x 0.62 inches) . Space-saving and portable. It can be used for about 100 days with CR2477 battery.    Bluetooth distance range This product supports a barrier-free distance of 50 meters between the mobile phone and the transmitter   Small size and low power consumption, the product size is about 1.5 x 1.5 x 0.62inches.   It can measure indoor high temperature, low temperature and normal temperature, and the measurement speed is fast and the measurement temperature is accurate.   Smart Bluetooth app, connect up to 100 at the same time.   Temperature range: -20-60 ° C (-4-140 ° F); humidity range: 0-99%.   Support temperature data export function, record a group of data every 10 seconds.   Use CR2477 battery,and battery can be replaced.