Sonoff SPM-Main LAN Smart Switch: Monitor and manage your energy consumption effortlessly with this multifunctional switch. Compatible with both Ethernet and Wi-Fi, it supports up to 128 channels with the option to connect up to 32 SPM-4Relay switches separately. Ideal for various applications including residential and business monitoring.

• Energy Consumption Monitoring: Precisely track electricity usage in apartments, offices, or server rooms using the accompanying eWeLink app.
• Overload Protection: Automatically shuts down connected devices to prevent damage when thresholds set on the app are exceeded.
• Reliable Connectivity: Connects via Ethernet or Wi-Fi, and communicates with SPM-4Relay switches over RS-485 for stable long-distance transmission.
• Extensive Channel Support: Supports up to 128 channels through integration with additional SPM-4Relay modules.
• SD Card Storage: Keep a 180-day log of energy metrics using an SD card (8-32 GB, SDHC) for data export.
• Easy Installation: Mount easily on a guide rail for convenient setup.

Note: SD card is not included.