The iPhone X has only been out for a few days, but we’re already seeing people take advantage of the face mapping technology on the phone in numerous ways. Some, like Animoji karaoke are more entertaining than useful, but others — like Warby Parker’s new app — are a little more useful (as spotted by Joanna Stern on Twitter.)

The glasses company is cleverly using the iPhone’s camera to take maps of people’s faces, and use that data to recommend styles of glasses that will best fit your face. It’s a step beyond the digital try on system the company has previously offered, where it would try to place a virtual pair of glasses on a picture to let you see how it looks.

Warby Parker using the iPhone X TrueDepth camera is super super smart: pic.twitter.com/LgHpO8hfUx — Joanna Stern (@JoannaStern) November 7, 2017

It’s a pretty neat idea, although its hard not to see the potential that could be waiting in the wings here. Why stop at just using the facial recognition to recommend glasses, when you could do full augmented reality try ons, similar to how Snapchat does its face-mapped lenses?

The new feature is available on the Warby Parker app on iOS now, although it should go without saying that you’ll need an iPhone X to take advantage of it.