I bought it from a small provincial store in Evia because there was an issue with the electricity in the area and there were constant power outages. When I first tried to turn it on, it didn't even light up, its battery was completely dead. I returned it and the store owner replaced the battery with one of his own because all the other UPS batteries were dead as well. With the new battery, the UPS has been working perfectly since then. It has experienced many power outages and voltage fluctuations, but it has shown to respond perfectly. I also once took it in the car and connected it to an electric vacuum cleaner to clean the car, and it cleaned it perfectly!