2-Pack Quiet 40mm USB Fans with 3 Speed Control, Mini 5V DC Brushless Computer Case Fan for VR Gear Raspberry Pi Cosplay Helmet Mini PC Aquarium Roku Router Cooling Ventilation

The problem I had was that the external hard drives connected to a NAS built on a mini-pc in a homebuilt rack would run warm if a backup started while I was out of the office and the air-conditioning was off. The possible solutions were either to leave the A/C on all the time, which was stupid; or to buy some fans, which seemed like a much smarter choice.So I bought these fans and banged a few more pieces of wood onto my homebuilt rack to hold them in place. They're just wedged in there between the wooden rails on the top and bottom, pointed so the air flows toward the back, over the four external hard drives.The idea works. I had the A/C off most of the say and there were no S.M.A.R.T. warnings. The drives seem very happy now.These fans have no speed control, so they run full-bore all the time and are a bit loud as a result. I was going to wire one in, but I don't hear so well anymore anyway so I decided not to bother.The fans seem well-made. They move a lot of air. I didn't measure how much air they move, but it's enough for my purposes. The hard drives are now cooler.The finger guards should guard adult fingers okay; but I think a toddler might be able to get their fingers in there if they tried hard enough. I don't have a toddler handy to test that hypothesis, however; so I'll just advise you to not use these fans where toddlers with a love of science might want to test my theory.In summary, they're good fans. They spin around and move air, and they do it very well. Since that's all I expect of a fan, I'm giving these air-movers five stars.

My Alienware video editing laptop was running HOT, even with a big 200mm dual fan cooler base under it. I added these little fans and just set them blowing down into the air intake grill above the keyboard. The laptop internal fans barely spin up anymore. And before I added these little guys, that laptop was LOUD. I appreciate that they're discretely plugged into the dual-USB-jack pigtail. I also appreciate that they are 3-speed. I never have to run them on anything but the lowest setting, and they keep my laptop VERY cool now! A great deal if you have an application like this. Or, I would imagine they'd be great for supplying fresh air/exhaust for a cosplay outfit or helmet, etc. They run for hours a day and seem fine. I'd buy them again.

The cords are short and I needed to supply the plugs. It makes noise, but it isn't loud. I don't think I would purchase again, just because of the cord length. It works good 👍

These fans were perfect for what I needed for my battery charging case. The fan control works well also.

Fan was nice and quiet initially, but after just over a month got very loud. Guess the small bearings just can't stand up.