Review on 🌀 Noctua NF-A4x20 5V Premium Quiet Fan (5V Version) – Efficient Cooling with 3-Pin Connector, 40x20mm, in Brown by Elvis Kimbro

Noctua makes good fans and this is no exception. I bought it to use in my router (which doesn't have a fan but gets very hot). Used for Omni connectors to power via USB cable through the speed controller (basically just a potentiometer in the box). I'll say this: At high speeds, it's quieter than most 40mm fans, but it still sounds like a RC airplane taking off. Don't expect it to be quiet, just quieter. I ended up taking it off and just putting a bigger fan underneath it, which is more efficient and completely silent.