Meet the Fallback: an elegant battery extender for your phone. It has a pop-out portable battery design, allowing you to insert and remove batteries fast. You can insert a battery though the opening on the case’s inner side and remove it to avoid adding any extra bulk to your phone. You can carry and use multiple batteries with this system.
Inventor Designtouch is behind this idea. The Fallback is essentially a battery case with a detachable battery. It charges your phone and does not increase its size when you don’t need to charge it. Pretty smart, isn’t it?