inputs.text: proven winner book - spent weeks looking external battery sort keep iphones yes carry personal iphone 4 iphone 3gs work ipad2 charged ready decided new trent arcadia pack imp70d looked best choice based decision not price fact designed safely charge three devices well reviews read time also helped reinforce decision device easy use well built conveniently sized fit shirt pocket takes little space briefcase battery charges using existing iphoneipad2 charge cord plug using usb cable provided ive able charge three devices couple times still yet charge battery second time isnt something intend use every time need charged plan use backup get jam travel find need charge no outlet available meeting far performed beyond expectations im happy