Wderair 4 x 120mm Server Rack Mount Fan 12V with 100V - 240V AC Power Variable Speed Control, High Airflow for DIY Cooling Mining Rig, AV Cabinets, Home Theater, Refrigerator, Greenhouse

This is 2x240mm fan arrays with dual ball bearing setups. The bearings they claim are good for 50,000 hours. While not as good as some bearings out there, like FDB which is rated between 100,000 and 120,000 hours or SSO/2 from Noctua which is rated for 150,000+ hours. But to put 50,000 hours into perspective, that is 2083 days or 5.7 years of constant use. I am using this in a unique way, where I am using this to extract heat into our basement from a small fin array I installed to warm the basement at the end of the loop. It works amazingly well, and saves me from having to install a 2ft length addon that is 79 dollars and wouldnt improve efficiency much being open as it is. (This takes more of that heat out at the lowest RPM speed than a second array would offer while being passive.) Because I only need the one array, I stored the second one away so as to offer up a replacement in, hopefully 5 years. This is a AC powered setup though, with a dial a speed knob. I found that barely up from slowest speed helps out enormously. I doubt you would need all four fans for a a router setup mind you, but they accurately said you could use this for Mining Crypto. (Just be careful as those are transient assets with no physical assets to support it.) It would work great for cooling open rigs though. At highest speed though, these are very very loud, at the speed I have it at though, it is sub ambient with other noises naturally overwhelming it. Like the rustle of leaves outside despite being in the basement and closed cell foam insulating between the floor joists which is very faint in sound. I can say I am happy though and this was worth it. I would likely just by the single 240mm array next time though, if I see another opportunity mind you.

I make my own method to cooldown the tube of CO2 Laser Engraver, and works perfect to me.

These fans blow... but in a good way! It has a speed controller and is fairly quiet for 120mm fans. I set mine up on my desk to dry the hot glue that Im using for a sculpture Im creating. Theyre able to stand on their own even at 100% power, so I just place them on each side of the piece and leave it on as I work.

I got the fan for my bathroom air circulation, with these fan i can blow out the condensation after a hot shower, very easy to instal and the fan is also quiet, I LOVE IT !!!!

Good airflow. Easy to control on your own instead of dealing with automated fan curves and no slowdown under 30% and other such junk. You can use it to cool off computers or other high powered electronics inside of a entertainment center.

High quality fans with a variable speed controller. Note that when youre moving as much air as these three fans combined are capable of, theres going to be a bit of noise. It will help if you use foam tape or some other rubber- or compliant-mounting method that isolates these, and that will help ensure the least noise. Recommended.

These fans sound almost like a drone when you run them at high speed, though not quite as loud as a drone. That being said, I dont need to run them at high speeds, as they give good airflow even at lower speeds. I have them running at about 30% or so, and they keep my AV equipment cool without any significant noise. I used two blowing air in near the bottom and two blowing air out at the top, and I can actually feel the airflow in various spots in my cabinet with my hand, even at that low speed. I can see these being useful for a wide variety of applications.

4 Large PC Fans that can be assembled in various configurations with all the supplied Nuts, Bolts, Standoff feet, Rubber pads and connecting tabs.

These fans are solid, appear to be good quality. I got them for my greenhouse, so will have a more detailed review after next summer, and will update then. But in the meantime they do move quite a bit of air, so should help keep the greenhouse ventilated.

I ordered these to cool down some network appliances I have installed inside a closet. I have the 3 fans pulling air from a vent in the closet onto the appliances. They are extremely easy to install, just plug them in and dial in a speed. They can be configured to be completely silent to moderately noisy. Running these at their full speed is still lower volume then a server fan but audible from across a 20ft room at midnight. During the day running at full speed I could not hear these from across the room. Running these at a moderate speed produced enough air for my scenario and produced a very low audible volume.