Review on 🌬️ Hon Guan 4-Inch Air Duct: Optimize Airflow and Ventilation with Premium Quality by Rene Putman

It's attached to a cheaper plastic push/pull fan where it squeaks into our sunny room from the other side. If this is attached, only air movement can be heard, no fan noise. While not listed as a silencer, it does the job quite well. Also, it's very thick yet flexible so it looks like it will last a very long time and I didn't have to worry about it tearing or breaking when I was working with it.