It runs off both wall power and car accessory power. It comes with swappable plugs for Europe, UK, US, or Australia, and runs on 120 or 240 volts. It has two USB outputs - I thought this was pointless until I discovered how useful it is in car trips if two people can charge at the same time. In addition, one of the ports provides 10 watts for charging tablets (when plugged into AC). The charger also lights up - red indicates charging, and green indicates the devices are charged.