The Flair Puck measures environmental conditions, controls temperature and sends infrared signals to mini splits, window ACs and portable devices.
When a Puck is plugged in to AC power and connected to your home WiFI, it's called a Gateway Puck. When a Puck is running on batteries, it's called a Sensor Puck (Sensor Pucks can optionally be plugged in to AC power).
You will always need at least one Puck configured as a Gateway when using Flair.