Sonoff’s Smart Stackable Power Meter (SPM) is a professional category, DIN-rail compatible, stackable relay with power meter and overload protection, with up to 20A per channel max. capacity. It can save consumption to a memory card (not an accessory).

This is SPM’s 4-Relay unit, with 4-gangs of relays and power meters, with max. 20A per gang maximum output. SPM Main unit is sold separately.