The Duo will start shipping on 10 September, with pre-orders going live today in the US. However, it's unclear whether the device will come to the UK at launch, particularly considering no international pricing has been confirmed.
For US$1,399.99, you'll get a version with 6GB of RAM and 128GB of storage, while stepping up to 256GB will set you back US$1,499.99. That's roughly in line with many high profile folding phones, including the Samsung Galaxy Z Flip and new Motorola Razr.
The Duo itself is comprised of two 5.6in OLED displays, at a resolution of 1800x1350. They're connected by what Microsoft is calling a "revolutionary 360-degree hinge", while both screens can combine to form an 8.1in, 2700x1800 workspace. In this form factor, the regular 4:3 aspect ratio becomes 3:2, creating the more boxy look that we've seen on other recent Surface PCs.
That's lead to Microsoft suggesting that the Surface Duo will be a great productivity device, although I have my doubts.
The Duo is powered by Snapdragon 855 processor, and not more recent 865. That means there's no 5G support of any description, primarily because the Duo was designed and unveiled before Qualcomm's latest chipset was launched.
While Microsoft is not explicitly describing the Duo as a smartphone, its ability to make calls and connect via 4G means it must be considered as one. That makes cameras of particular importance, and the company has already highlighted its photography prowess.
The device comes with a single 11Mp, f/2.0 lens, complete with dedicated low-light mode and 7x "super zoom". It's also capable of 4K video up to 60fps, although this is with electronic and not optical image stabilisation. The design of the Surface Duo means this same lens can be used as a webcam when folded, which should result in high-quality video calling.
While they cannot be detached, both screens can work independently of one another. This means each has a battery of its own, with a combined capacity of 3,577mAh. While this seems a bit on the low side, Microsoft has assured us that the Duo will provide "all-day battery life".
Of course, it's impossible to verify these claims without being able to test for ourselves. In the meantime, you can read more about the Surface Duo here.