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

I replaced the fan on my Icom ID-4100 with this and wow, what a difference. The original fan literally sounded like a jet engine and was extremely annoying. Finally replaced it with this fan and the difference is night and day. I literally can barely hear this fan when it is on high yet it seems to move plenty of air. Definitely recommend this one if you need quiet airflow on electronic equipment.

Great little fan. Good value, nice cable length. Not the best look, but if you need the airflow, this is the way to do it efficiently and without a cumbersome 120/140mm fan. It's actually more effective at cooling your HBA cards by being placed directly over the heatsink fins.

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:-)

These are a drop-in replacement for the stock Cisco ASA 5550 fans. No re-wiring or adapters required. The job of removing the screws from the lid takes more time than replacing the fans. I tried the rubber mounting things, but wasn't happy with them not mounting tightly against the case, which reduced the air movement, and increased the noise level, versus just mounting them with the included screws.They are maybe a smidge quieter, but not a lot. With that said, it's worth noting that I didn't use any of the power adapters which possibly offer a lower voltage to make them quieter? I could speak on this better had I read the manual, which of course I didn't.If I were able to change anything about this purchase it would be the price point for each fan. I don't need fancy packaging, nor the mounting rubber things, nor any of the power adapters. I need a better price instead. If the company could offer a bare-bones fan only option that would be better. These older firewalls are less than $100 used nowadays, so its a difficult decision to spend nearly that much on replacing the 5 internal fans.Another thing to note, is that the fan on the power supply is still noisy. I doubt it's as easy to replace- it probably hasn't a plug-style connection.Noctua, you could sell more if you offered a fans-only pack for specific use-cases, like mine.

Awesome fan, I couldn’t believe it was even turned on until I held my hand up next to it. Incredibly quiet. Highly recommended.

THIS IS A GREAT PRODUCT, but it is NOT going to help reduce the noise of rack mounted hardware.The thing about rack mounted computers and switches is they're intended to be extremely reliable and robust. This means the fan controllers are wired to monitor and maintain speed. This means:1. The wire pinout is different than this product and this fan will not spin.2. Using an adapter to the correct pinout still doesn't make the fan work.3. The hardware fan controlller monitors fan speed and defeats the resistor dongles by increasing voltage to compensate, resulting in precisely the same RPM anyway.My Dell brand switch just sat there with a red light, refusing to boot. Granted, Dell uses propriety connectors for everything to force consumers to purchase only their products, but this is a fan with a standard connector.Plugging this fan into a PC and 3D printer works perfectly and the fan is VERY QUIET compared to other fans it's size.