If you aren’t satisfied with just one screen on your new iPhone, now you can have another one. The popSLATE case designed by Greg Moon and Yasha Behzadi makes use of that untapped resource that is the back of your iPhone. PopSLATE uses an E-Ink screen, similar to that of a Kindle, which only uses your phone’s battery when the imagery on the screen is changed. The popSLATE case uses the iPhone’s accelerometer to interpret “tapping” to change the screen. This technology allows further personalization of your iPhone, which is one of popSLATE’s greatest features.