Sonoff Smart Stackable Power Meter Main Unit

Communicated by RS-485: The Sonoff SPM Main communicates with the Sonoff SPM-4Relays via RS-485, which enables multi-terminal and stable long-distance data transmission.

Overload Protection: Once the Sonoff SPM overcharge protection is activated, it protects your device from burns.

Works With Alexa & Google Assistant: You can directly ask your Amazon Echo Dot or Echo Show and Google Assistant speakers/smart displays to turn on/off your Sonoff SPM outputs independently.