Review on Raspberry IUniker 30X30X7Mm Brushless RetroFlag by Andres Callahan

These fans are working as advertised. Separate cables allow you to decide whether to connect the fan to 3.3V or 5V cables, giving you the option to choose high or medium cooling speed. I lowered the temperature of my Raspberry Pi 3B+ from 50 degrees Celsius to 37 degrees Celsius. I now feel confident running the Pi-Hole 24/7 without worrying about a catastrophic hardware failure months later. Passive cooling from a heatsink might be enough for occasional use, but if you leave your Pi powered on all the time, active cooling is a must. If you're good with your Dremel, there's no reason to buy a special fan housing). Thirty minutes and 25 cents of window shielding material was all it took me to add active cooling to my formal 7-inch touchscreen case.