Source: Gadget Review
Everyone has had experience dealing with a short phone battery. As people use their phones over time, the battery undoubtedly becomes weaker. In fact, after a couple years of use, it is not unusual for a phone to have a battery life that merely lasts hours with typical use. Fortunately, there have been several solutions to solve this problem. People can purchase a new battery, carry their cord and charger with them, or rely on a clunky external battery.
Now, there is the perfect solution from Mophie. This company makes external batteries and has designed an external battery that both fits cleanly as a phone case and plugs into the back of the phone where the charger would sit. This means that the phone is no larger in the pocket than a phone with a typical case and provides a simple switch on the back to begin charging the phone. For charging the external case, it comes with a convenient USB cord that can plug into the same wall charger that charges the phone directly. Without a doubt, this is an ingenious design that solves the problem of a short battery life. Check it out here!