SONOFF Smart Stackable Power Meter

【Connect up to 32 SPM-4Relays】One SPM-Main can be connected 32 SPM-4Relays. Each SPM-4Relay has 4 isolated channels to help you manage devices more conveniently. 【Max. 20A/Gang】Each channel can support maximum current of 20A, no fear of high power load. 【Overload Protection】Once the overload protection is enabled, it can protect your devices from burning out. 【Micro SD】SD card plays a more significant role, like export electricity consumption data quickly, store more than 20 years of historical electricity consumption and each meter relay can save 20,000 operation logs. 【Power metering】Obtaining current, voltage, and power easily. You can monitor the consumption statistics of 4-Relay by checking eWeLink App on your mobile phone. Note : The Main Unit and 4-Relay of the Stackable Power Meter need to be used together. The Main Unit is connected to at least one 4-Relay to function. Note 2: The Main Unit capacity supported 8-32GB SDHC card. Click to buy Kingston Micro SDHC Class 10 Memory Card-32GB.