Noctua NF-A4x20 FLX Computer Case Fan - Cooling Components (Computer Case, Fan, 4 cm, 3700 RPM, 5000 RPM, 4400 RPM)

I purchased an unmanaged 5 port, 10gbe / 100gbs network switch to put in my makeshift networking closet. Closet is about 6 feet from my work station. Switch works GREAT, but has a 40mm fan that is legit 40db loud on the tech sheet for it but more like 50db in real life which is like having a conversation with a person loud.To remedy the issue, I purchased this fan. The fan itself is of the high quality and acumen for brown color tones one would expect from Noctua, so I'm not even going to touch on that.What is the most amazing about this purchase is everything else it comes with the kit and how Noctua caters to the primary use case for their customers here.My OEM fan has a 2 pin connector to the PCB. Noctua includes a converter so you can splice the OEM 2 pin together with the converter that plugs into the 3 pin coming from the fan. In addition, Noctua provides 3 tool-less (mostly) connectors for the splice. When you crush them down it squirts some kind of non conductive oil into the connections to protect it from water and dust. Made by 3M, but nevertheless a WELL thought out solution to include for their customers.Running at 4000+ rpm is extremely unnecessary for this network switch & since silence is the name of the game for me a way to reduce RPM without implementing a PWM controller in my limited space configuration. Another whammy from Noctua for this problem. Two RPM cables are included that step down the rpm without the need for a separate controller. I used the ultra low noise cable. It reduce the noise some, but the fan itself made such a difference that alone should do the trick for most people.I've purchased a lot of PC components and networking hardware over the years. Not sure I've ever felt like a company thought this much about their customer for something that costs such a small amount of money. The time and frustration they saved me is immeasurable and priceless.Good job Noctua:-)

I have bought lots of these over the years, and as is typical for Noctua you're getting a high quality product that is QUIET. I bought these fans to replace the ones on a network switch since I know Noctua is quieter, and while they did not work on the switch I intended them for because the switch is wired different, I used them in another one and they work perfectly.Yes some may say they don't flow as much as the industrial grade, super loud fans that come with them, but in a home environment that matters much less and I'd rather have peace and quiet thanks to Noctua.That being said, this is a small fan, small fans spin faster and are louder by nature, so I'd still recommend either using the included Low Noise Adapter Cable (labeled in the box), or implementing some sort of fan control. At 50% speed these are basically whisper quiet, and move some decent air. I also have the PWM versions of these which are easier to control for speed, but you get the idea.One small con is that the rubber dampener things that come with these are basically useless because they don't seem to stay in on the small fans. I've used them on the 120mm fans and they work fine but for these they don't really work as well and the fan slips off.

I'm going to start off saying this is my first stand alone Noctua fan I've bought, mainly because I always needed 24V and in this size they don't make one. With that said I've read multiple posts around the interwebs where people have used these 12V fans in a 24V printer with no adverse problems. I decided for $15 it was worth a shot to try and see. In the past I've bought dozens of DC fans from 30mm to 120mm for various applications and most come in somewhat basic packaging. The Noctua very much surprised me as the packaging and presentation was very nice and presented well. I was even more surprised when I opened the package to see all the extras included like wire extensions, in-line speed reducers & anti-vibration mounts. The wires are heat shrinked with abrasion resistant sheathing everywhere else on the wire.Before cutting the wire I first tested it on a 12V DC power supply to check that it worked followed by 24V. It worked fine with both voltages, it might have been a little faster on 24V but it was hard to tell because it's rather quiet on both voltages. After removing some wire wrap I cut the wires to my desired length and crimped then soldered on my 2P JST connector (red & black wires) leaving the yellow wire unconnected and secured under the new heat shrink. I then installed on my printer where it's been in use almost constantly now for 18+ hours and still going strong.I'll continue using this as long as it works and if anything changes from the 24V use, like it dies, I'll update my review commentary.Update 04/28/2022: This fan is still going strong on 24V and easily has 1500hrs on it. I've since bought multiple more fans for other printers and projects all working just as well including in my Voron 2.4 ABBN with no heat creep even though the interwebs all claim the low static pressure will cause your hotend to melt like chocolate in the sun.