Amazon got into the home security game this year, first by buying Ring and then through the launch of full home security packages. As part of its massive Alexa event today, the company is announcing a new security feature that anyone with an Alexa device can take advantage of. It's called "guard mode," and it can be activated whenever you tell Alexa that you've left your house. It's made up of a few smart alerts, specifically when your Echo (or other Alexa speaker) hears the sound of breaking glass or detects an alarm from a smoke or CO2 detector. In any of those cases, it'll record a clip of the sound and send it to your phone so you are aware of the alert.