Power meter/ energy monitor/ electricity usage monitor analyzer.
Watt meter, Power meter for measuring wattage, voltage, freqency, current, kwh, power factor. E.T.C. It has storage capacity to store data and has backup battery. It also has date and time.
all electrical engineers, solar and inverter installer and users, electrician, technician and everyone using electricity must have it and most importantly, every inverter and solar installers and users.