Amazon announced this morning that it has begun to roll out Alexa Guard to all Echo customers in the U.S. The feature lets the company’s line of smart home products double as home security devices while the user is out. Say “Alexa, I’m leaving” on your way out the door, and the Echo device will start listening.

The key feature here is something called “Smart Alerts,” which listen for key sounds, including breaking glass and smoke and carbon monoxide alarms. If the Echo hears the noise, it will send you an alert, coupled with an audio recording of the noise.

It’s an interesting new addition and one that leverages the sometimes controversial fact that the device’s mics are designed to always be listening. Amazon points out that it worked with licensed contractors to break hundreds of different glass windows with different instruments in order to create a wide range of different sounds for Alexa to listen for.

The new feature works with different smart home devices, as well. Users with Ring or ADT pro monitoring can set it up to forward alerts to their providers. Users with Away Lighting setup, meanwhile, can use the alert to flip on lights in order to make it look like you’re still around.

The app is rolling out as a free addition to all Echo owners in the U.S.