Review on Vortex Atmosphere VTBDD4 Backdraft Damper by Paul Mac

Not fitted yet but looks good. Couldn't find this type of product at my local hardware store. The rubber gasket idea is there. The downside is it didn't come pre fitted. It took a while little fiddling with needle nose pliers to install the two vertical rods that hold the flaps in place and then attach the spring.I run this at 203 CFM in line with a 4" fan and it will feel about Located 25 feet from the fan. The air pressure in the setup works great to open the doors. The sleeve is the same size as the 4" tube before swaging or you have to swage the inlet tube, and even if the lapping isn't in done the right order you will also need to crimp the outlet tube or try to expand the 4" round tube around the outside of the outlet. this back cushion.