Customers can automatically reduce heating and cooling inefficiencies in their home and indoor garden with ZoneMaster™ Dampers. Once installation and wiring are complete, the damper will open and close to allow airflow according to predetermined temperature triggers. With one crimped and one straight duct end, this non-directional twelve-inch damper is easily secured into existing ventilation duct work of the same size. A UL-Listed transformer is also included and must be wired to a remote thermostat (available separately) for the unit to operate correctly. ZoneMaster™ Dampers are made in the USA and covered by a three-year manufacturer’s warranty.