... 3. built-in battery: 3.7V,2200mAh mobile phone potable power charger:It has unique circuit design, which can indicate the charging ... improve the battery’s service efficiency.The connecter is standard USB design, inner there is 2200mAh Li-battery.Fashionable design, ... output is less than 5V, e.g iPod, iPhone, PAD, mobile phone, digital camera, MP3, Mp4 and so on. mobile phone potable power charger