Was it this?
https://www.amazon.com/Noctua-redux-900-Ultra-Quiet-Award-Winning-Affordable/dp/B07C5KZX85

https://www.amazon.com/Coolerguys-Power-Supply-Length-Multi-Functional/dp/B084JG4619

But probably will get this:
https://www.amazon.com/Coolerguys-Powered-Receiver-Component-Cooling/dp/B00DCCJQ0S

I use one of these on my AVR since I only have about a 2" gap above it. I didn't bother with a thermal switch--it just runs constantly.