Built-in rechargeable battery: can be powered by external DC5V power supply or standby battery. To use the backup battery, open the back cover and switch on the detector. Temperature unit is optional (Celsius or Fahrenheit). View temperature history records at any time. Supports multi-user supervision: share the device with other users via the app. Built-in buzzer sounds when the detector is triggered. Compatible with Tuya Smart or Smart Life app; supports Android and iOS smartphones. Plug type: US plug, suitable for use in Canada, Mexico, Thailand, the Philippines, and other regions with compatible outlets. Voltage: AC100-240V. Color: As shown. Material: Plastic. Package contents: 1 x Tuya WiFi Temperature Sensor. Note: Other items not included. Due to lighting effects and monitor settings, the actual color may vary slightly from the image. Measurement error allowed within +/- 1-3 cm.