It is literally silent and I have installed it on the Be Quiet Pure Rock cooler. The CPU cools satisfactorily and I haven't heard the slightest noise.

Replacement of three front case fans 120mm from coolermaster, which you thought constantly launches an airplane in your house. My impressions are the best after the change, I truly have no words! You think the computer is not even running! The best purchase I have made for a PC component!

Be Quiet is a name that lives up to its reputation. I used it as a replacement after a short circuit in the CPU cooler fan. It remains silent even when running at 100% to cool a 9th generation i5 processor overclocked to 5.1GHz with full utilization. It may slightly lack in airflow compared to more expensive models, but this is due to its use as a CPU fan. I consider it ideal for use in a professional case for someone who is not interested in flashy lights and excessive frills, but rather reliable and quiet cooling.

For their price, they are fine, although they remain quiet until 40-50%. At 100%, they are quite annoying. I bought only 3 because I didn't want to spend more money on expensive ones. The 20db that it claims is actually a lot, but for less than 10 euros each and after years in this field, you know what you're getting

An economical purchase for fans. I have 3 of them and they are quiet. Be careful before you buy them to check the connectivity.

5 stars even though low airflow and cooling capacity.
If you put 3 in front like me and work them permanently at 70-80% (depending on the soundproofing of your case, you can even go up to 100%), you will barely hear them.
And even at 100%, in a case with moderate or no soundproofing, the sound made by one or all 3 together is not annoying at all, in my opinion.
These are the quietest fans I have ever bought. In contrast to the previous Enermax D.F.Pressure 120mm fans I had, which made a light but annoying sound like creaking from 900 (<50%) rotations.

Completely silent up to 1000 rpm, you can hear the airflow but without any other annoying sounds at higher speeds. I use two, one for the CPU cooler and one for exhaust, and I am completely satisfied! The only complaint is that the screws are not included in the packaging...