Enjoy having complete electronic control of which rooms your HVAC system heats or cools with the Suncourt ZoneMaster 6-Inch Normally Open Motorized Control Air Flow Damper.This inline damper can be configured to open and close partially or completely depending on your application and preference. This adjustable airflow damper can be integrated with an existing zone controller system or any controller supplying 24 volts AC or can operate as a standalone device using the included transformer.With the electronic duct damper, an appliance module, and any X10 timer, you can reduce your heating or cooling expenses by cutting off airflow to unoccupied rooms during work hours. Or, if you want grandma and grandpa's bedroom, for example, to be a little colder or warmer than the rest of the rooms in the house, any mechanical thermostat can close the damper when a pre-specified temperature is reached. Take control of the climate in the rooms of your home or business that may not need to be heated or cooled at all times with the Suncourt ZoneMaster 6-Inch Normally Open Motorized Control Air Flow Damper.