neverest® ESD 80mm in-line Duct Sound Absorbing Tool Sound Insulation Silencer for Round Ventilation Pipes

The sound absorber work very well. I had to mod them slightly in order to fit into the 4" waste pipes that had been used for the vent holes. I did that by fully wrapping the sound absorbers with 50mm wide Armaflex self sticking foam tape.Initially I did wrap only one of the sound absorbers and left the other one slack. So I found out, that not wrapping the sound absorber does lead to a poor performance, if the internal diameter of the tube is wider than the outer diameter of the sound absorber. In 100mm ventilation duct tubes the wrapping would not be required.The permanent noise from the stream outside has reduced dramatically. Entering the kitchen the first few days felt like coming into a void spot, as if something was missing.Although please take into consideration that the noise reduction does not happen magically. If you expect your fan to be less audible and the fan is fitted on the inside then the noise reduction would be on the outside only.

Having had an air vent causing noise issues, but covering it only causing damp issues, this was a life safer. Though the noise isn’t fully dampened, it’s made a huge impact, and option to remove and add segments again makes it versatile enough to make a difference. The soft sponge makes its installation easy

I accidentally bought two and used both with good results.I have a flue on the side wall, being in a coastal location the wind can be significant. We've just had winter gales for a couple of days and these have significantly reduced the noise, but also the sucking and blowing from that vent as the wind blew.No more blow back from the fireplace, and less noise from the wind :)

5 to 10 db reduction in sound level

Very effective

We installed these as we're living in a coastal area that gets quite a lot of wind and there is also a road adjacent to our house. The draught doesn't seem as noticeable, however I don't see any change the to level of sound coming in through the vents

Just what i needed!It’s incredible how hard these things are to find.Bought pre-brexit taxes.Now it would seem like a lot of money for a piece of cheap material.

Only effect was to increase the motorspeed on the fan. Wasting more electricity. Did nothing acoustically. Use acoustic ducting if you want to reduce sound, and cover your fan with a baffling agent - duvet or whatever. Depends what you want it for or if cost in electricity is a consideration.