Smartphones like the YotaPhone have taken advantage of E Ink displays by giving the battery-efficient screens the ability to take over certain functions. Android devices with E Ink panels are rare, though, this is why the Oaxis InkCase is such an awesome accessory.
This case allows you to turn your iPhone 5S, Nexus 5 or Galaxy Note 3 into a dual screen device. We got to test the Galaxy Note 3 one and walked out quite impressed. This case puts an e-ink display on your device, which then connects to your smartphone via bluetooth.
It allows you to control calls, music controls, fitness tracking, notifications and more. All these functions are controlled via an app, so really the E Ink screen is kind of a battery-efficient remote control for your phone. Of course, you can also read, and battery life averages at about 5 days!
Of course, your phone will not last all those days, but you will save some battery by not needing to turn on that LCD screen. It will be available via KickStarter later this month, so you may be able to get yourself one of these soon!