I am adding this paragraph after owning this battery for about 12 months:  For a time, I was having trouble with this battery.  It would die and only wake up when plugged in to a charger. Then it would immediately show at least a half charge, sometimes more.  However, this glitch has gone away and it is working OK again.  Here's a possible user error:  I was charging a failing iPhone 3 and it had lots of other problems besides a weak battery.  It's possible that one of the problems with that phone was a short or near short in the charging jack.  I would have done some experimentation but then my daughter gave me her iPhone 5 in exchange for an iPad.  I am having no further problems with this battery now that I am charging a known good device.  My advice, from this single experience, is to give this product a try if you like it, or another New Trent external battery.  They answer emails and offered to evaluate this battery after I started having problems, but I decided not to bother since the problems have now stopped.  I'm raising my rating back to 4 stars, and if the problems don't come back at all, I'll raise it back to the original 5 stars I had on this review initially (below).