This is replacement mount for this great NAS case https://www.printables.com/make/2330181?comment_id=2402938
I had to modify fan mount because I couldn't find 92mm low profile fans for adequate price. So I used one 120 fan, and it works great for 4 hard drives
Note that if you add two more drives around the edges, airflow could be not so great for them
The author marked this model as their own original creation.