Google Duplex—the Google Assistant's restaurant-booking phone call bot—is finally getting a wider rollout. The tool was previously only available on Google's Pixel phones, but now you can send out a robocall from most smartphones. An updated Duplex support page (which was first spotted by XDA Developers) now shows support for "iPhones with the Google Assistant installed" and "Android devices running version 5.0 or newer."

Google Duplex is one of the more impressive products Google has shown off in recent years. Just ask the Google Assistant to make a restaurant reservation at a certain time, and it will do it. By "do it," I mean it will make a phone call to a business, speak to the business on your behalf with one of the most human-sounding computer-generated voices ever made, negotiate a reservation time, and get back to you.

Google's video is a good representation of how it works:

Last summer I was able to take restaurant reservations from Duplex—Google had a few journalists pack into a New York City Thai restaurant and field phone calls from its voice AI. Over the low-quality codec of a voice call, Google's voice technology sounds almost indistinguishable from a human, complete with emulated human flaws like pauses in speech and disfluencies like "um" and "uh" in the middle of a sentence.

There isn't just one Duplex voice, either. Google's voice technology was able to generate voices from a range of artificial people, with different personalities and styles of speech. Duplex also does an incredible job of understanding the real human on the other line, and it almost seems like a full generation ahead of the voice technology currently in the Google Assistant or Siri. If something does go wrong, though, Google has a call center of actual humans standing by.

Using what is probably the best voice AI on Earth to book restaurants, which you can already do over the Internet without speaking to anyone at all, seems like a waste, but Google is being very conservative with its new voice technology. For now, it's trained to book reservations and that's it. But even simply using Duplex up until now has been difficult. You needed the right phone—a Google Pixel—and you needed to be in the right location—at first four cities, now 47 states. With the wider device and location roll out, Duplex should soon be usable by most people in the US.

Listing image by Google