The fan is very small which is desirable. At 5 volts, it is also noisy. One problem with a 5 volt fan for a Raspberry Pi is that the Pi4 doesn't have 5 volts available. I had to drive the fan with an external power source, which is not ideal, but I took advantage of this by only supplying it with 4 volts. The lower voltage slows the fan down and gets the noise under control. I don't want to hear the fan. It does lower the operating temps when running. If I were making a suggestion, it would be to provide a larger diameter fan capable of silent operation at 3.3vDC. A nice case could be designed around a thin fan which is just slightly smaller than the Pi board.