There are a number of apps and services available to help you detect what song is currently playing around you: products like Shazam, SoundHound, or even Google Now. Such services typically rely on your smartphone’s microphone to record a sample of music and then compare that sample against a database of songs.

The Google Pixel 2 and Pixel 2 XL house a feature similar to what is described above, but with a couple of key differences: firstly, it isn’t something that you request, rather, something that will appear automatically on your lock screen. And secondly (and most impressively), it works offline.

The feature is known as Now Playing and you’ll find in your Google Pixel 2 settings. It’s disabled by default, but, when active, it will (attempt to) show what song is currently playing in your location on the Pixel 2 lock screen. You can also set Now Playing to show up in your notifications — and you’ll be able to tap on the track to go to a Google Assistant result for it too (thankfully, not direct to the Google Play Music page, which would be inconvenient for those who don’t use that service).

It’s a smart idea: the question of “who is singing that song?” comes up frequently for someone unfamiliar with chart music like myself. Having an automatic, unobtrusive indicator like a lock screen message seems like an elegant way to ping someone this information before they even think to ask.

But it’s not a completely comprehensive service, and it’s not designed to replace Google Now or others because it only works with “tens of thousands” of songs instead of the millions of songs that the others can pool.

The reason for this is indicated by the fact that Now Playing works offline. Unlike similar online products, which can utilize a gigantic database of songs, Now Playing can only pull the song from a pool that is held on your device where storage is limited.

This database is region specific, and is updated on a weekly basis in the background when you’re connected to Wi-Fi. A Google spokesperson told Venture Beat that the feature shouldn’t take up more than 500 MB of your internal storage space — so you can see how supporting millions of songs would occupy far too much memory.

While I love the prospect, there is a question over what kind of effect Now Playing is going to have on battery life. Connected to the internet or not, anytime you enable an “always-listening” service it’s going to impact battery life. It’s likely a small drain like having your NFC always on, but it may be more dramatic.

We’ll have more on the Google Pixel 2’s features, and a comprehensive look at its battery life, in our upcoming review. What are your thoughts on Now Playing? Let us know in the comments.