If you thought this was going to charge up your iphone4s then think again. It looks neat, cool design features... but does not fully charge, in fact when I used it when my phone was dead it barely got to 20% then went dead itself. Takes ages to charge up itself too. I then fully charged the mophie again and tried charging my phone..... again only made it to around 23%. Knowing how energy hungry iPhones are this is a total waste of time in my opinion.... I emailed mophie and they suggested.... guess what? Upgrade to a larger model! I wanted something small not a clunky big object. I know this is only a top up.... but come on.... poor effort!!