T-Mobile has flipped the switch on its 5G network, setting it live over areas of the US that it says covers 200 million people. While the network is supposedly live today, no one is going to be using it until later this week: the first two phones to support it go on sale this Friday.

The “nationwide” 5G deployment relies on a slower form of 5G, using T-Mobile’s 600MHz spectrum. This “low-band” 5G essentially takes airwaves like the ones used for LTE and bundles them together with some new technology to deliver faster speeds.

T-Mobile doesn’t offer specifics on what kind of speeds you’ll see on the new network, and the actual improvements will vary a lot by location. “In some places, 600 MHz 5G will be a lot faster than LTE. In others, customers won’t see as much difference,” a T-Mobile spokesperson tells The Verge.

The launch offers low-band 5G across the US, not mmWave

Because T-Mobile is relying on LTE-like spectrum — which travels relatively far — the carrier is able to deploy it over a wide swath of the country. It’s the first major wireless carrier to claim nationwide 5G coverage.

What T-Mobile isn’t claiming are nationwide offerings for the fastest form of 5G: millimeter wave (mmWave). mmWave relies on much faster airwaves to deliver much faster speeds, but the signal doesn’t travel very far and is easily blocked by almost anything in its path. T-Mobile has already started to deploy mmWave in a few cities, but there’s no word today on whether that’s expanded. mmWave deployments are likely to stay confined to densely populated areas, like cities and sports stadiums, because of its physical limitations.

On Friday, T-Mobile will begin selling the OnePlus 7T Pro 5G McLaren Edition for $899.99 and the Galaxy Note 10 Plus 5G for $1299.99. Both are capable of connecting to its 600MHz 5G network, and all T-Mobile and Metro plans include 5G access. The phones do not support mmWave.

The two phones do have some ability to get faster speeds down the road: T-Mobile says they both support mid-band spectrum that’s currently owned by Sprint. If the merger between the two companies closes, T-Mobile will redeploy that spectrum as part of its 5G network, further speeding up these phones’ connections.

All of the major US carriers have been racing to launch 5G this year. At this point, they’ve all deployed it in some form or another, although it’s mostly been in select locations and with select technologies. The next notable deployment is supposed to come from AT&T, which plans to launch its own low-band 5G this month, albeit only in five cities.

To promote the launch, T-Mobile made this very goofy ad featuring its current and future CEOs as well as its CTO: