Sturdily built! My use required the fan to blow the opposite direction. To do this required the back to be removed and switching the red and yellow wires. Now it works perfectly in the opposite direction. I also added a grommet to protect the wire as it goes through the metal frame.
Only thing troubling that I found is the ground (green) wire was entirely disconnected when I opened the fan! It was stripped but just floating there not touching anything. Not a huge issue since this isn't a product that a consumer will normally be touching while using but it's just a silly QA mistake. There is a sticker on the inside of the frame showing the ground should be connected there. I added a small lug to attach it to one of the frame screw.