Here are a couple of photos of my fan installation in my 4×4. It’s a Blue Blower Professional 14″ High Velocity Internal Oscillating Fan from Home Depot. I have one sitting on the floor and the other suspended from the tent frame. They oscillate inside their guard so there are no external moving parts. One less thing to worry about. I really dig them and it was really easy to hang one from the tent frame. And I really like the metal blades… way less dust sticking to them than plastic blades, improving your CFM. I noticed they come in a larger size, which would work well in a grow room as well, I suppose. I also really like not having the fan head hitting stuff as it moves.