The Yotaphone 2, which has screens on its front and back, is now on sale in the UK, priced at £555 and available at a pop-up shop in Shoreditch, east London.
From the front, the Russia-made Yotaphone 2 looks like any other smartphone, with a 5in Full HD display and Android 4.4 KitKat - but turn the handset around and you'll find another 5in screen on the back, but this one is e-ink, like a Kindle book reader.
Being touch sensitive, the rear screen, known as the Always-On Display, can be used to control the phone in exactly the same as the front screen, but far more efficiently, making the battery last much longer.
But is a dual-screened smartphone great or a gimmick? We asked passers-by in London for their views.