Google on Wednesday officially unveiled Project Fi, its wireless service that will start to go live in the United States soon.

In some interaction with friends on Wednesday, I noticed that there’s a bit of a misunderstanding about Google serving as a wireless carrier. For one, it’s not exactly going after major carriers just yet — though maybe someday it will. Instead, it’s actually working with them.

The service offers competitive prices, at least if you don’t use a ton of data each month, but it only works with one phone right now, the Nexus 6. I decided to create a quick list of things you need to know to clarify some of the confusion that might be out there in regards to Project Fi.

 

1. It runs on Wi-Fi, T-Mobile and Sprint networks

This is a key point: Google is technically acting as a mobile virtual network operator, or MVNO for short. That means it doesn’t operate its own networks, but rather off networks provided by other carriers. In this case, Google will switch you between Wi-Fi and networks operated by Sprint and T-Mobile.

Yes, Wi-Fi calls are included. It will figure out which signal is the best and keep you connected. Sprint and T-Mobile compliment one another nicely in this case: T-Mobile offers fast data speeds in select areas, while Sprint can keep you better connected in some cases, like indoors.

2. You need a new SIM

In Google’s FAQ, the company reveals that you’ll need a new SIM card. The company hasn’t said how it will issue those SIM cards yet, whether you’ll be able to walk into a Sprint or T-Mobile store to pick one up, or if Google will send you one directly. But you won’t be able to use your existing T-Mobile or Sprint SIM to access the network, and that’s because it uses both networks.

The good news is that your number isn’t tied down to your phone, however. Here’s what Google says: “We also want to help phone numbers adapt to a multi-screen world. With Project Fi, your phone number lives in the cloud, so you can talk and text with your number on just about any phone, tablet or laptop.”

3. International data is included

Google explained that 3G (up to 256kbps) international data roaming to more than 120 countries is included, which is awesome though not that quick if you’re used to surfing on LTE. The roaming is more than likely part of the agreement with T-Mobile, which also offers its customers the same option.

It’s unclear if you’ll be able to upgrade that data while traveling abroad, but you won’t need to pay for expensive international data plans, and you’ll remain connected right when you get off of the plane. Text messages are free to and from more than 120 countries, too, while calls will cost about 20 cents per minute.

4. You won’t pay for data you don’t use

You’ll pay a flat starting rate of $20 per month for domestic talk and text, unlimited international texts and Wi-Fi tethering, Google explained. Then, each 1GB of data you want will cost you an additional $10 per month.

So a plan with 1GB of data and talk will cost you $30 per month, while one with 10GB will cost you $120 per month. The best part? You’re only going to pay for the data you use. “The value of your unused data is applied as a credit toward your next month’s bill,” Google explained. “For example, if your data budget is 3GB and you use 2.2GB, you’ll get $8 (for 800MB of unused data) to use next month to lower your bill.”

You’re still responsible for taxes, so those will appear in your monthly bill but will vary depending on where you live. “Taxes and government surcharges vary per state, but are normally between 10-20%,” Google explained. “For example, if your monthly bill is $40, the taxes on your statement could be between $4-8.”

5. You can keep your number

You can keep your phone number when you move to Project Fi, but that doesn’t necessarily mean you won’t incur any fees for leaving your carrier. Unlike initiatives from Sprint and T-Mobile, Google isn’t going to pay off any of the fees associated with an early contract termination, so expect to pay those costs. If you’re not on a contract right now, you’ll be able to switch seamlessly without any costs.

While we’re discussing your phone number, it’s important to note that Project Fi doesn’t currently support family plans, so you won’t be able to manage multiple accounts. Also, there aren’t any contracts, so you won’t be locked in if you ever want to leave.