The WiFi Power Meter SONOFF SPM-Main Master Unit is used to perform intelligent management with overload protection, electricity monitoring and statistics. WiFi Power Meter SONOFF SPM-Main Master UnitThis Power Meter communicates with the cloud via WiFi or Ethernet cable, and with its Slave Unit via RS-485, enabling long-distance, stable, multi-terminal data transmission. Both the Master Unit and its Slave Unit have a standard size that allows it to be placed on a DIN Rail. Installation is very simple. Pairing instructions with the eWeLink application: 1. Download the "eWeLink" app from APP Store for iOS or Google Play for Android. 2. Press the button for 5 seconds until the LED indicator flashes rapidly. Choose the appropriate pairing mode 3. The device will be automatically searched for and connected. 4. Enter the ID and password of the home Wi-Fi network. Applications of the WiFi Power Meter SONOFF SPM-Main Master UnitIt is the ideal solution for controlling the energy of your