Wearable devices are all the rage right now, and the vast majority of them aren’t cheap. But alongside the unveiling of its new Mi 4 flagship this morning, Chinese smartphone maker Xiaomi unveiled a new wearable of its own that’s super affordable — and it offers some nifty features, too.

The Mi Band costs just ¥79 in China, which is just $13 in American money. You might think it’s not up to much, then, but you’d be wrong. It’s actually quite impressive, with up to 30 days of battery life in between charges, IP67 water-resistance, and the ability to unlock your smartphone when you’re near it.

The Mi Band packs a whole bunch of clever sensors for fitness tracking and monitoring your sleep, and the little LED lights across it can alert you to incoming notifications on your smartphone. They can also combine with the built-in vibration motor to provide you with a discrete alarm clock.

Xiaomi didn’t reveal too much about the Mi Band today, but it’s clear the company has big plans for the device. It even teased the ability to one day unlock doors and activate other digital objects with it. For now, we’ll just have to wait and see when — and where — it will be available.