If your smart phone feels like an extension of your hand, it can be quite tragic to experience a dead battery ? often when you need your phone the most. In order to combat this fairly ubiquitous problem, Mophie has created an assortment of battery cases designed to extend the battery life of a smartphone. These 2100mAh battery cases add up to 120-percent extra battery life, and protect your smartphone or tablet from disastrous bumps or drops as well. Whether you have an iPhone 5, iPad, or a Samsung smartphone, these cases easily attach right to the smartphone, and some models even offer built-in storage to give your smartphone a little extra memory. Fortunately, when you are looking for your own Mophie iPhone 4, Mophie iPhone 5, or any other battery cases, you can head right on over to eBay and browse among the many brand new and slightly used options from reliable sellers. Never miss important calls or respond to your emails in fear of a dead smartphone or tablet battery by feeling the extra charge of Mophie rechargeable battery cases.