This product is an air booster fan that's designed to be installed directly into your existing floor, wall, or ceiling vent. It fits a standard 4-inch by 10-inch duct opening.
 
 
The unit is essentially a fan with a decorative cover that sits on top of your register. It's designed to improve the airflow from your heating and cooling system into a specific room. By pulling air from the duct and pushing it into the room, it helps to more effectively heat or cool an area that's hard to reach, like a finished basement, a room at the end of a long duct run, or a space above a garage.
 
 
The fan typically has an adjustable thermostat or a sensor that automatically turns on when it detects warm or cool air coming from the vent, and it shuts off when the system turns off.