Roughly three years after first launching the service, Google said it has added an unlimited data option to its Project Fi MVNO. Google’s new unlimited feature, which Fi calls “bill protection,” caps charges for one line at $80, even if a customer uses more than 6 GB in a month. Plans with two lines get protection at $120, three lines at $135, and four lines at $150. Customers don’t have to do anything special to prevent getting charged for using more data, Google said.

“Bill Protection gives you the peace of mind to use extra data when you need it. In months when you use more than 6 GB of data, we’ll cap your charges for calls & texts plus data at $80, and allow you to continue using high speed data for free—similar to an unlimited plan,” wrote Google’s Project Fi manager Marcia Jung on the company’s blog. “And here’s the kicker: with Bill Protection you’ll never have to pay for unlimited data in months when you don’t actually need it. If you only use 1.4 GB of data, at the end of the month you’ll pay just $34 instead of $80. So no matter how much data you use, you can save money with Bill Protection every month.”

Thus, Project Fi still charges users $10 per month for each GB of data they consume, but if those users consume more than 6 GB in a given month, they can just pay $80 for unlimited usage.

Jung added that users who consume more than 15 GB of data in a month (which she said less than 1% of the service’s users do today) will have their speeds slowed; Engadget noted users’ speeds would be slowed to 256 Kbps. And Jung said that users can continue to pay per GB if they don’t wish to have their speeds slowed.

“If you’re a current Fi subscriber, you’ll see it appear on your next billing cycle.”

Jung added that the new “Bill Protection” service will also work for roaming users and for data-only SIM card users.

Google launched its Project Fi MVNO in in April 2015, boasting the service would automatically switch users to whatever network was the best, be it Wi-Fi, T-Mobile or Sprint. In the intervening years, Google has added two additional major wireless partners (three in Europe and U.S. Cellular in the United States), a family plan and other options. The service only works on a select few phones, including Google’s Pixel devices.

The addition of unlimited data to Project Fi is likely a reaction to the rise of unlimited wireless services from all of the nation’s wireless operators. While Sprint and T-Mobile have long offered unlimited data options, Verizon and AT&T joined the unlimited data scene with their own services early last year.