This very useful accessory serves for two main goals. First, it protects your lovely iPhone case, and, secondly, contains an additional battery which can prolong “life” of your cell phone till next charge. Details in a video below and on manufacturer’s website.
 

Only one week left till day Х, therefore we all look at these images  with an increasing skepticism. Though, as always it is necessary to speak in such cases - you never can tell. Look cool, no doubt. Let’s wait one more week.