The company also announced three new smartphones: two of them, the Lumia 950, 950XL, are worth designating "flagships," while the 550, notably, will sell for $139, putting it in the territory of cheap grey-market Android phones. More interesting than spec bumps, though, is Continuum for Windows, a Window 10 feature which made its official debut at the event. Continuum is one manifestation of the pocket-computer idea that others have had as well in various forms: it means that with an adapter, a phone can be used as the CPU and graphics engine when connected to a screen and keyboard: "The adapter features a Microsoft Display Dock, an HDMI and Display Port, plus 3 USB ports to provide productivity on the go and let you plug in additional peripherals, such as mice and keyboards. Other accessories can be connected too, Microsoft said."
Microsoft also demo'd the Surface 4. Its improved screen is 12.3" at 2160x1440, for a pixel density of 267 PPI. The new pro has a Skylake 6th-gen processor, which they say provides a 30% performance boost over the Surface Pro 3, and a 50% boost over the MacBook Air. The SP4 goes up to 1TB of storage, and up to 16GB of RAM. The Type Cover was improved as well — the touchpad is 40% larger and supports 5-point multi-touch, while the keys have better travel and pitch.
On top of this, Microsoft also unveiled the Surface Book laptop. Its defining feature is that you can unclip the 13.5" touchscreen and use it separately as a tablet. The keyboard dock has a dedicated GPU that will boost performance when attached. Microsoft is using a new type of hinge that bends and extends at multiple points, so you can also reattach the screen backward if you want to use it as a tablet while keeping the extra GPU power available. They claim a 12-hour battery life for the Surface Book.