The Xbook Duo is an Xbox One and Xbox 360 combined into a laptop, allowing you to play both consoles from within one slim machine.
Both of those are available to buy commercially (for a price - $1500 and $1395 respectively). But the Xbook Duo is not.
Zarick constructed the Duo as a proof of concept after going round to a friend's house to play Call of Duty and not being able to switch between Xbox 360 and Xbox One easily enough. As you do.
Microsoft did not include backwards compatibility for Xbox 360 games in the Xbox One, but Zarick's machine manages it by powering down one console and quickly switching the display and internal power brick to the other.
And it works! And, like the other the other laptops, it actually looks rather smart.
Here it is in action: