DuroZone 8-Inch Power Close, Spring Open HVAC Motorized Damper – Normally Ships Same Day, Convertible to Power Close, Spring Open – 24V AC, 5-Year Warranty

Just had this installed by a professional, driving its power from an HVAC-designed transformer, which itself is power with a home automation switch, which is coupled with a home automation thermostat. It controls air flow into my office and turns off a few minutes into a heating cycle to prevent the office from over-heating. We are now entering the cooling season, and I might also use it to prevent the office from becoming a freezer. The issue with the office it has a lot of computers that heat up the room, so I need more cooling than I do heating - this device gives me that flexibility.Super easy to install, slice open the duct, shove this in, tape it up, attach it to something for physically support, and wire it in. It does take about 20-30 seconds (roughly) to close, especially since it is "open until it is completely closed", but only a couple seconds to open. It has a foam lining for the paddle so it makes a good seal, but I don't require a perfect seal.I would definitely buy more of these as I need them.

I have a storeroom where I draw cool, early morning air into it each day for a couple hours. I use a timer so the damper opens and my fan blows. After couple hours timer shuts off, damper automatically closes and fan stops. With damper closed the cool air stays in the storeroom until the next morning. Does exactly what I need it to do. Seems to be solidly contructed too. And it is easily reversible.