U.S. start-up creates a $420 smartphone with rear e-ink display, biometric earprint sensor and more

U.S. start-up creates a $420 smartphone with rear e-ink display, biometric earprint sensor and more:

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With smartphones tending offer near identical features, a number of manufacturers have sought to break the mold and bring something new to the table. On a number of occasions, we've seen handsets with more than one display, with LG having recently dropped the V10 featuring a smaller screen for additional functionality. There's also the YotaPhone 2, which by contrast, has opted for a rear-facing e-ink display. An interesting concept, it's one that American start-up Siam has latched onto with its Kickstarter hopeful 7X device.

Where YotaPhone is ...