Noctua NF-A4x20 5V PWM, Premium Quiet Fan, 4-Pin, 5V Version (40x20mm, Brown)

I use M2.5 screw and M2.5 nut as washer.

I am really impressed with the amount of additional cables, connectors, and mounting options provided. I ordered the fan to place inside of a fursuit (costume) head. It is very quiet, if even one person is talking you cannot hear it running. The air flow is low, but it is constant and hands free so that is very nice. I thought it might be much louder than it was which is why I ordered the PWM version. Since it is *so* quiet theres no reason to not let it spin at full speed unless your application is severely power limited.

Kind of forced to use noctuas because the only other 40mm 5v 4pin fans available are tied to the Jetson nano and they straight didnt work for me so i had to get these puke colored babies which worked like a charm.

I was blow away by the quality of this fan. The details, the material feels like it will last a really long time. You can tell people did lots of research.

Installed on my Jetson Nano. Works great.

Its quiet and blows, it goes great in my 1u server.

Product advertised as quiet, sounds like a rocket ship. Too loud for silent setup use. Will be returning.

Bought to replace noisy fans in a 1U unifi router enclosure. These are noisier, though theyre also much higher CFM.

Installed on a Jetson Nano. I had to buy M2.5 x 8mm screws / washers and nuts. Fan will not turn unless the tempature is high or you turn it on via a software command.

Very high quality fan. I needed to cool down a bit a bucket converter(step down from 36V to 12V), and this fan keep the converter very nice and cool. Too much heat is not good for you baby, that how the song says?