When you wave with your hand in front of the device, a glowing ring or light appears on the Space Plus and Space Pro respectively. You can configure the glowing ring/light to indicate the following:
A white light: my device is connected to a hub
A colored light: based on your chosen CO2 thresholds the sensor will show a green/yellow/red ring.
By default, the glowing ring/light is white. In the dashboard, you can change the settings to enable the CO2- alert.
You can read more about the CO2- alert here: https://www.airthings.com/business/co2-alert
How to enable CO2 Alert:
On the Dashboard, click on Buildings from the navigation menu and choose the building for which you want to activate the alert.
Go to the tab Settings.
Scroll down in the menu to Glow indicator behavior.
Here you can choose if the devices should display a CO2 alert and you can configure the thresholds and the alert frequency.
The CO2 alert can only be configured on the building level. So you can't configure device by device.