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

I bought this fan for use with the Nvidia Jetson Nano. The Nano automatically turns the fans on and off on demand. Cant tell is the fan is on by noise generated because there isnt any. The only problem I had installing it was because the supplied screws were too short and didnt fit the holes in the heat sink. Temporarily used round toothpicks to hold it until I can find the proper screws.

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

As it was advertised

Perfectly silent, and brilliantly cools my jetson nano 4gb.

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.

These are the best fans ever. Very quiet, easy to spin, move a lot of air and made of quality materials. They are a little on the expensive side, but thats because quality is more expensive.

This fan is quiet, feels well built and works perfectly with my Jetson Nano kit.

Unless Im running something intense, the PWM fan is usually off. Then when the Jetson Nano gets warm the fan turns on just enough to cool it. I never notice this fan - I have to look at the blades to see if its spinning because its so quiet. The default fan I replaced came with a third party acrylic Jetson Nano case, it was not PWM, always running full speed and a noisy little fan at that. Ive seen other comments on the default fan saying its not very loud. I suspect the low quality, default case fan varies in noise from unit to unit. If you want quiet - Get the Noctua PWM! I got the thick one, so I had to find some longer screws. I should have gotten the thin one which I expect would work fine and use the existing HW. At any rate, if quiet and sanity are worth a couple coffees to you, get the Noctua PWM fan, such an improvement over the default fan that came with the third party Jetson Nano case.

Title says it, this fan does a great job at cooling a raspberry pi 4. With a little modification to the case

Installed easily with screws I had laying around. Turns on when its needed and off when its not. The only complaint is the rubber corners on the top of the fan eventually rubbed off and one day one of them jammed the fan blade up and almost overheated my nano. But I took the rest off and its fine now.