When using phones, we mostly pay attention to the front side of the gadget where the screen is, while its rear isn’t usually considered to be of any importance. Ukraine-based startup Concepter, known for its crowdfunded smartphone flash iblazr, has decided to put the back of your iPhone to use by giving it simple notifications for calls and text messages. Surprisingly, the $50 “smart case” dubbed Lunecase, a Kickstarter campaign of which began on Tuesday, does not have a battery of its own. Moreover, it lacks any connectors as it only needs to catch electromagnetic waves that iPhone emits when receiving a call or a text to both power it and determine what exactly is happening. As a consequence, call or a text notifications appears a second before the phone starts ringing and disappears after a call has finished, or three seconds after a text is received.