During its Build 2015 keynote, Microsoft just unveiled a new Windows 10 feature it's calling Continuum for Phones. It allows smartphones running Microsoft's latest OS to transform into desktop PCs — or at least an experience that's very close — when connected to larger screens. We've already seen Continuum help ease the transition for users switching between tablet and PC modes, and this is an even better example of what's possible when developers go along with Microsoft's universal apps plan.

Read next: Our Microsoft Windows 10 review.

The company is giving developers the tools to create software that runs across PCs, tablets, convertibles, smartphones, and Xbox. Apps can automatically adapt to the screen size they're running on, and Continuum for Phones is a showcase of that unity. Microsoft's Joe Belfiore demonstrated apps like Excel and Photos running in a traditional desktop view with the Windows 10 smartphone hooked up to a monitor. He also showed that content can be copied from phone-centric apps like Messaging and pasted into desktop apps.

Everything basically looks like the full version of Windows 10, but the phone is powering everything. "What we're trying to show here today, is our unique vision for phones and enabling them to scale up to a full PC-like experience," said Joe Belfiore. Continuum for Phones won't be something you'll find on existing Windows Phone devices. Belfiore was quick to note that the feature will require new devices capable of driving this dual-screen feature. Microsoft plans to share more on that soon.

Developing. Check out our Microsoft Build 2015 Live Blog for the latest updates

★★★

Microsoft Build 2015: Keynote speech in nine minutes