Oh that's one of those Cougar fans, I just bought 2 of them for my case since the stock ones died after 4 years of continuous use. They're really nice and quiet with the rubber mounts.
they really are. I am strongly considering replacing the other stock PWM fan with one. They look AWESOME and are very quiet, but unfortunately have lower airflow. (box says around 75CFM, while the stock fans must push over 100CFM).
BTW: anyone have good liquid cooling ideas or methods? It would be pretty sweet if the antminer boards could be placed into immersion cooling, but i know that they would require a radiator capable of >400W for each antminer which i imagine is costly and semi-complex to install