The iDroid is one of the key items Snake has in Metal Gear Solid V: Ground Zeroes. Snake uses the phone-like device to contact Hinds, view the maps, and check mission objectives.
Metal Gear Solid director Hideo Kojima showed an iDroid case designed by Sentinel on Twitter. The case adds a little flashlight to your phone and other gimmicks. More details about the case will be shared tomorrow.
Konami also has a Metal Gear Solid V: Ground Zeroes app that turns your smartphone screen into the iDroid map and has a Mother Base mode.