Telecom companies are racing to introduce 5G, the speedier successor to 4G LTE, to increase network speeds and allow for a host of new applications. The faster connections will let customers not just download movies in seconds, but also may enable virtual reality, autonomous cars, and other far out technologies.

Here’s how AT&T’s new 5G network works and where it’s available.

Where is AT&T 5G available?

AT&T’s year-old 5G service for business, called 5G+, is now available in parts of 23 cities. The carrier is using a slightly different model for its initial consumer 5G service—one that emphasizes broader coverage rather than faster download speeds.

Subscribers to AT&T’s two top unlimited data plans have access to 5G service in 10 cities: Birmingham, Indianapolis, Los Angeles, Milwaukee, Pittsburgh, Providence, Rochester, N.Y., San Diego, San Francisco, and San Jose. Customers on those two plans, which start at $75 and $85 monthly, aren’t charged extra to use 5G.

AT&T says the service will soon add several more cities to its 5G network: Boston, Bridgeport, Conn., Buffalo, N.Y., Las Vegas, Louisville, and New York City. Nationwide coverage is slated for the “first half of 2020,” the company has said.

Unlike AT&T’s business 5G and Verizon’s 5G offering, AT&T’s consumer 5G service should be available across large swaths of those metro areas and easily reach inside buildings. That’s because the service runs in the 850 MHz airwave band, a frequency that has been used for cell phones for decades and travels much farther than higher frequency bands.

How fast is AT&T 5G?

Like T-Mobile’s similar 5G service, AT&T’s consumer 5G service is making a trade off. To cover more territory, the system is forgoing the massive speed increase that comes with using less expansive but higher capacity frequencies like 28 GHz and 39 GHz. Services using those higher frequencies reach speeds of more than 1 gigabit per second, over 20 times faster than the average 4G LTE speed. AT&T hasn’t specified the average speed of its consumer 5G service, but T-Mobile’s rival service is only 20% faster on average than 4G.

What phone do I need for AT&T 5G?

Only AT&T customers who purchase a new 5G compatible phone will be able to access the new network, no matter where they live. And to start, the only 5G phone AT&T is selling is the $1,300 Samsung Galaxy Note10+ 5G. The carrier is offering an installment payment plans and generous trade in offers to cushion the blow. Many lower priced 5G phones are expected to hit the market next year.

Didn’t AT&T already offer a 5G service called 5GE?

Yes. But that service, officially called “5G Evolution,” isn’t actually using 5G technology. Instead, AT&T relabeled its fasted version of 4G LTE as “5GE.” The new 5G service could provide somewhat higher speeds than 5GE, although AT&T says at first they may be quite similar.