Vent Systems 150 mm / 6" Inch Backdraft Damper Stopper - Male Fit Dryer Vent Backflow with Shutter - Plastic One-Way Airflow Ducting Insert - Inline Fan Vent Deflector

simple & effective.

Works perfectly and seals well.

Good quality, easy to fit and so far, does a good job. Only time will tell if it lasts?

Fitted both of these and the rooms are noticeably warmer. Totally removed the draught coming in from the extractor fans. Will pay for themselves rather quickly I would think.

I bought 2 of these to replace older ones that were no longer swinging shut properly and they work well, keeping out the backdraft when the fan is not in use and keeping the bathroom noticeably warmer. Slides into standard 100mm ducting pipe.

The item received was a Polish Awenta branded one and is very well made. Butterfly seals properly on reverse flow, and a feature so you can be sure of its orientation once in place (it will only work with the tag at the top. I think). I'd also purchased a cheaper one and it is dreadful by comparison.

Very easy to install. Whoever installed the two extractor fans forgot to install the ‘one-way’ backdraft flaps that prevents toilet smells from being blown from one bathroom to another (the were connected to the same flexible 100mm tube with a ‘y-branch’. Remember to install then so the flap opens towards the exit or it will not work. They are directional.

Worked perfectly for what I needed. Feels solid and well-made, fits as expected, and does exactly what it’s supposed to. No complaints at all.