SONOFF S31 is a compact and lightweight US standard Wi-Fi smart plug with power monitoring. Both S31 and S31 Lite are ETL certificated, this means they reach the indispensable security and reliability standard that a smart plug must have.Ā Note that power consumption and over-load protection are available for S31.Ā The smart plug lets you control home appliances via eWeLink APP anywhere, anytime. Also, third-party platforms like Amazon Alexa and Google Assistant can seamlessly work with this plug for a voice-controlled home. The small size makes the smart plug will not occupy another outlet of your socket or power strip during, which reserves more space for other plugs. Convenient to use, plug and play. Bring a S31 home, keeping track of the real-time power, current and voltage of your home appliances via APP to view which one is power-hungry and power-saving. You can also measure electricity consumption for a specified period. Besides, Features over-load protection which allows you to set the power, current and voltage value for your appliances, and this smart plug will automatically turn off connected devices in case of reaching any one of the set value. S31 provides you 100 days of historical power consumption data record (support to export) and monthly electricity bill forecast. Monitor and understand which appliances are consuming most, then create scheduled or countdown timers to keep your electricity bill down. For other features like smart scene, sync status, share control, these are the same as S20 smart plug.