The Flair Bridge is a robust networking device that connects to your home network. You can connect it to your home network via Ethernet or via an available 2.4 GHz Wi-Fi network.
Once connected to your network the Flair Bridge will talk to the Flair cloud and will serve as a hub to which your Flair end devices (Sensor Pucks, Smart Vents) will connect.
Once you are using a Flair Bridge most or all of your Flair Pucks will be able to be configured as Sensor Pucks, which delivers many benefits including more accurate temperature readings, and the ability to run the pucks wirelessly (i.e. via batteries).