Long-rumored, Microsoft's first post-Windows Mobile phone isn't really a phone at all. Sure, it makes calls, but that's just one feature of the Surface Duo. This book-like device has a pair of thin 5.6-inch screens that unfold to form an 8.3-inch computing surface. It can be used as a tablet, like a mini-laptop, or as something altogether different when the 360-degree hinge is bent so both screens face outwards. It runs Android, instead of Windows 10X like its big sibling the Surface Neo, and will available for the 2020 holiday season.