I wanted to use this fan as a substitute for a power supply fan (already had 120mm fans of BQuiet that are almost inaudible). Before I testhalber connected it to 12V and I thought at first that he did not go because I had possibly connected something wrong. When I looked closer I saw that it went very well, but it is inaudible, at least from 20-30cm distance (in an even shorter distance actually still do not hear the air flow, but the fan). No doubt if this ventilator is built somewhere, he will not be heard. For me, he did bring me out of the question because I realized only later that the original loud fan of the power supply about 40 cfm (cubic feet per minute) through blew, but this "only" 14cfm. That was my fault, because the power supply which I wanted to make quieter, just had too much power, but what I had previously not considered for normal devices (NAS, etc.) this fan is probably very appropriate. I'll keep it and use it when needed somewhere that equipment manufacturers save because it often on the fan. Although I feel that everything potters around the house that then but should do quietly and softly is this fan, just inaudible.
What also stands out, this fan pulls super little power, I have measured by time, there are 0.05 amperes, so only 50 milliamps! (Photo attached)
Conclusion, super fan, super quiet and very economical.