After years of discussion, Comcast is finally getting ready to launch its wireless phone service.

The service will be called Xfinity Mobile, and it’s supposed to launch sometime in the near future.

It isn’t going to be widely available, however. Xfinity Mobile will only be available to Comcast’s existing customers — the company’s goal here is to build an even bigger bundle for existing TV, landline, and internet subscribers.

Comcast is piggybacking on Verizon’s network

Most Comcast customers will be able to subscribe to an Xfinity Mobile plan with unlimited data for $65 per month per line, but customers with some of the more expensive X1 TV plans will be able to get it for only $45 per month. Comcast will also offer a pay-as-you-go service for $12 per gigabyte.

Those prices are slightly cheaper than typical wireless plans, and Comcast is hoping a few other perks will draw customers in: it won’t charge arbitrary line access fees; it’ll let families have some phones on the unlimited plan and others on the pay-as-you-go plan; and it’ll let pay-as-you-go customers switch in the middle of a month over to an unlimited plan, without penalty. It’s also offering 24/7 support over text message.

At launch, Xfinity Mobile will support phones from Apple, Samsung, and LG — though only a selection from each. It’ll have the last two years of iPhone models, it’ll have Samsung’s S7 and S8 models, and it’ll offer LG’s X Power, a midrange phone with a large battery in it.

Comcast’s offering is going to be pretty different from the typical wireless service. Rather than owning and operating its own cell towers, Comcast is essentially renting wireless space from Verizon — so Comcast’s customers will actually be connecting to Verizon’s network. That means Comcast will immediately have nationwide reach.

Smooth Wi-Fi handoff is going to be critical to Xfinity Mobile’s success

But because Comcast has to pay Verizon for the data it uses, Comcast’s wireless plan is designed to push customers onto Wi-Fi as often as possible. Customers aren’t just paying for access to wireless service, they’re also paying for access to Comcast’s network of 16 million Wi-Fi hotspots.

Comcast says that phones connected to Xfinity Mobile will be set up to automatically find and connect to any nearby Wi-Fi hotspot. That data won’t count toward monthly caps, and it’ll likely be delivered at faster speeds than what’s offered over Verizon’s wireless network. Comcast also clarified that no services would be zero-rated over Xfinity Mobile, including its own Stream TV offering. It won’t be offering voice-over Wi-Fi either.

This unconventional format has been tried before by companies like Republic Wireless, but it has yet to catch on in a big way. For that to happen, Comcast will have to prove that it can make Wi-Fi handoffs happen without interrupting customers’ connectivity.

Comcast executives seemed surprisingly unaware that this might be an issue. During a call with investors, someone asked if Xfinity Mobile would do anything about the “shitty” handoff ordeal people often experience on phones, and executives laughed and said they’d have to make it a new goal.

“I would say that we get it. Wi-Fi today is not what it should be,” said Comcast Cable president Dave Watson. “We have room to improve. But I would say this: one of the things that I talked about today is, just like X1, just like other product areas, our aspirations are to constantly improve the Wi-Fi experience.”

Xfinity Mobile has been in testing inside of Comcast, and today the company is beginning to expand the test to all of its employees. While Comcast didn’t give a firm launch date for Xfinity Mobile, the company said a consumer launch would follow internal tests “soon thereafter.”

Disclosure: Comcast is an investor in Vox Media, The Verge’s parent company.