Review on 🏢 Hon&Guan 4 Inch Round Air Vent ABS Louver Grille Cover White Soffit Vent with Fly Screen Mesh - Ideal for Bathroom, Office, and Kitchen Ventilation by Andargie Waiker

I have a 4" 150 cfm inbuilt exhaust fan. I originally purchased another duct cover which I had to return because it restricted airflow and made a loud squeaking noise when the fan was running at maximum speed This cover, on the other hand, is much quieter and fits perfectly in the duct thanks to the friction of the black plastic wings. It's still noisier than without the cover, but the noise level is acceptable. There's a removable plastic screen/screen (for bugs when it's outside is used?) which makes the cover even quieter when removed. There aren't many options for 4" exhaust covers so I'm glad this item is available.