Sonoff SPM-Main Smart Switch Wi-Fi/Ethernet Power Meter Sonoff SPM-Main smart switch that allows you to measure power consumption. The device is the main element of the system consisting of SPM-Main and SPM-4Relay. The device supports wired connectivity (Ethernet RJ45 port) and wireless Wi-Fi. The product is very versatile - it can support up to 128 channels! To do this, it must be connected to the SPM-4Relay switch (max 32 pcs). SPM-Main is equipped with overload protection to avoid damage to your devices. In addition, thanks to the built-in microSD card reader, you can protect your energy consumption history from up to 180 days ago! Specification: Manufacturer: Sonoff Model: SPM-Main Color: White Input: 100-240V ~50/60Hz 50mA max. Wi-Fi: 802.11 b/g/n 2.4 GHz Material: PC V0 Dimensions: 142.5 x 90 x 66.5 mm Compatible microSD cards: 8-32 GB (microSDHC) Key features: Multiple applications - The SPM-Main switch has many different applications - it allows you to m.in check how much electricity your tenants use per month, what is the energy consumption in your office, protect expensive equipment in the server room - the switch has overload protection. Device Connectivity - SPM-Main communicates with the cloud via an RJ45 Ethernet port or Wi-Fi. The connection to the SPM-4Relay switches is via the RS-485 port, thanks to which it ensures stable transmission over long distances. Support up to 128 channels - One SPM-Main module allows you to connect and control up to 32 SPM-4Relay switches. Each SPM-4Relay offers as many as 4 independent channels with a maximum load of 20 A each. Thanks to this, SPM-Main can handle as many as 128 channels! This makes it an ideal solution for apartment blocks - it allows you to check the energy consumption of 128 apartments. Power Usage History on microSD Card - The product allows you to save the history of energy consumption measurements for the last 180 days. The switch is equipped with a microSD card reader (8-32 GB, microSDHC). This gives you the ability to conveniently export data and ensure that important information is secured. Note: microSD card and SPM-4Relay are not included.