I've ordered this device to determine costs of electricity consumption. In addition this device is probably not suitable. Sometimes it shows a consumption of, sometimes not, although a constant load is connected from almost 1200 Watt !!! Now I have even in the event that was incurred during a kilowatt price of about 0.25 and a consumption of 2,977 KW / h an overhead factor of 0.04 ??? Since the device supposedly can not be returned, I advise anyone from buying this device. What it also indicates mostly agrees neither consumption nor the expense price.