ANVISION 2-Pack 40mm x 10mm DC 5V USB Brushless Cooling Fan, Dual Ball Bearing

To be honest, I was pretty worried that the fan was going to lack in performance due to its small size and cheap cost, but I was pleasantly surprised to find this isn't the case at all! I'm using this fan to push some air through a box with some hot components to help with cooling, and although this fan isn't silent, the noise didn't bother me.Pros- USB connection means no soldering and easy use with a power bank.- Very cheap (and comes with 2 fans)- Very good airflow for such a tiny low power fan- Thin and small design if perfect for mounting in a little project caseCons- I'm a little worried about accidentally tugging on the exposed (glued in) cables near the base of the fan- Relatively quiet but I still wouldn't want this running near me all the time- Does NOT come with any screws, washers, or other mounting hardware as opposed to the Noctua fans.

One of the out of the box issues with using the Raspberry Pi is the fan staying on even when the Pi is safely "shutdown". Since most fans are connected to the 5v gpio pin, power will continue to run the fan and there no way control it from those pins. One option is to use a moffet pcb to cut off power to it without damaging the fan but then you may require soldering which can problematic for some folks.The other option is to use a NPN transistor to control the fan from another gpio directly. This is actually a good way to handle it as you can code how you want the fan to function, when to activate it based on powering on the Pi or even based on the current temperature. But, you'll have to properly wire the transitor and do some coding and that maybe scary for some folks too.The easiest way to handle the fan is of course, by using a USB fan. Basically, if the Pi is on, power is sent to the USB port to turn the fan on. If the Pi is off, power is turned off from the USB port thus turning off the fan. No coding, soldering, or transistors needed. Granted you will have to give up a USB port but totally worth it for me.I'm using this fan for a game console rebuild and it's perfect for what I need. Runs quiet and keeps the Pi cool at 45 degrees consistently. Definitely recommend this one for anyone doing Raspberry Pi projects.

For the past couple of months I've been using these fans to push air through narrow ducts and to improve cooling for Raspberry Pi cases (only one of which is pictured). So far they've provided very consistent cooling for all intended purposes with stable reliability, and while you can hear the fans a slight bit in a completely silent room, the sound is unnoticeable if other ambient sounds (computer fans, AC, etc.) are present in the room. When combined with two heatsinks and quality cases, I was able to drop temperatures below 30c on my Raspberry Pi 4s. The only issue is that it's easy to snap the wires where they attach to the motor of the fan so be sure to exercise caution when installing them.Bottom Line: Overall this two pack is a great value buy for two USB 40mm fans, and given that you need both and don't mind the minor noise level, there likely isn't a better currently available for these unless you opt for a different method of powering them (like the GPIO pin versions).UPDATE 3/24: After running these fans on higher settings, they definitely make a lot more noise. If used for 3D printers with the intent of quieting them or for any application involving higher power settings, they become extremely noisy.

Used for the intake on an Xbox Series S. Paired with a usb hub. Surprisingly quite perfect size and good air volume. No complaints.

Works verry well

These fans are LOUD. I installed this on my Ender 3 Pro hotend and it is significantly louder than the stock fan. However, if you are dealing with heat-creep issues like I was, these fans are very powerful and are really good for regulating the heat break temperature, I haven't had any clogging issues since, but I am just not a fan of how loud they are.

came quickly and for being small they work .

I ordered these for my son who has an old security camera system (10 year old Swann), and the little fan in the system was getting noisy. He swapped it out with this new one and he was very happy with how easy the swap went and how much air the little fan moved.