50mm Fan 5V USB Brushless DC Cooling Fan, 4 Pack Speed 4200 RPM Fan for Small Appliances Series Replacement (4 PCS 5010 5V USB)

Bought to enhance the cooling of a 27" 2015 iMac. Removed the ram cover and placed a fan for additional air circulation. A bit noisy but it seems to do the job. I use it primarily when playing games so the sound isn't an issue and I can easily unplug the generously long usb power cord when I'm using the iMac for regular tasks. Good value for the money.

I purchased this product when I built a Raspberry Pi case with a built-in screen with my 3D printer right away I noticed it kept getting too hot so I bought these I didn't use the USB port I wound up cutting it and hooking it to the 5 volt from the Raspberry Pi and they don't drain that much power so far the kick on I have them programmed to kick on a certain temperature they're quiet so far I've had them running about 15 hours of use. And to be honest I haven't really noticed that much battery drain so they were perfect for my robotics project. So now I pretty much use them on any electronic projects that need Cooling. And it's nice because they come with an extra long cord that you can use for USB or cut it and hook it to a 5 volt Supply very handy. I recommend

I use this product as a cooler for a home made cloning unit. During the pandemic time was something we all had so I did research and decided I could build a cloner cheaper then what they go for on Amazon. The units are installed on the ends of my cloners dome and inside the dome I have a separate container holding water and the bubblers to feed the cuttings. The fans keep the water cooler than the ambient temp inside the cloners dome that I installed two strip led grow lights, and keep a supply of fresh air circulating. I know they say do not put in water or in humid areas but they work really well and in the event one stops working the fans are inexpensive and easily replaceable in my situation. The fans keep the water 2-5 degrees cooler then the ambient temp depending on conditions (day night winter summer) noise not really an issue for me since I have several other pumps and fans running it so don't bother me. In the end I really saved a bit of money but the first one I built took way more time than I wanted. Also my unit is half the size of some of the cloners so I saved some space. In a legal cannabis growing state where 12 plants is the limit you don't need a cloner with 36 spots. So for do it yourself projects these little fans have literally hundreds of uses not just for cpu or 3d printers.

This usb fan came in handy to provide air circulation in my semi closed terrarium.Works well on a smart timer. Low noise and can be easily placed where needed.

Put two on microPC on back of monitor, 80 deg F cooler but a little loud, work great and absolutely necessary!

These were cheap so expectations in check they work and are worth the money if you are ok with one being potentially faulty (seems I'm not the only one who got a defective fan in the bunch.)However, they are unreasonably loud for how little air they move. It's just a poor quality design - the fan blades and construction pay no effort to efficient airflow be it volumetric pressure or sound pressure. A slightly larger fan spinning at a fraction of the speed will move more air with less noise so if you can, go larger. I was installing these in Raspberry Pi cases and needed 40mm (or smaller) to cover the footprint of the case.Additionally, the USB cable is like 3 feet long, way overkill for anything you would use this for. I ended up clipping mine down and soldering the wires back together with heatshrink. Testing the fan uninstalled proved it to be quiet but after installing against a vent, the static pressure of the fan is terrible, which explains the turbulent noise.I'm going to buy one Noctua or some known brand and see if they perform better (they most likely will, but that needs to be weighed against the cost)

I used these for airflow fans in a fursuit and these work perfectly! Very quiet, good breeze and a nice long cord

I got the 4 pack 40mm 5V DC on USB cords.1 of the fans died after 2 or 3 months of using. I had gotten 2x 4 packs, so that I could use 5 fans.1 star for 1 of the 5 fans. 5 stars currently for the other 4 fans.Average of 1, 5, 5, 5, 5 = 21/5 = 4.2and this listing is merged with others that I have not tried, so I will average the score of the one I tried with the others, soaverage of 4.2, 0, 0, 0 = 4.2/4 = 1.05 star, rounded to 1 star.