Review on Coolerguys Dual USB Fan, High Cooling Capacity, 50Mm, High-Performance Efficiency, Dimension: [1.97 X 0.79 X 1.97 Inches], 5V, Ultra Quiet Cooling Blower Fan by Travis Carter

I've been using these fans for years in my home theater setup. I bought them when I noticed my Xbox was generating enough heat that the top of my entertainment center was extremely warm from the Xbox, which was in the first cubby directly below it. I bought these and initially just set them up standing on either side of the Xbox, one pulling air in and the other pushing it out, creating a circulatory airflow. It worked great, and after a few weeks, I was satisfied enough with their performance that I cut out a couple of holes in the back of the entertainment center and mounted them to the back. You could definitely feel the heat in the air these were pushing out, but the temperature difference around my Xbox was a major improvement. Plus, these things are super quiet! If you were in the room with no ambient noise and you really focused on them, you might be able to hear them. maybe. Even right next to them, they're practically running at a whisper as far as noise level goes.We eventually got a new entertainment center cabinet, and I relocated my Xbox to my man cave, but the new cabinet was fully enclosed, and I was sure that the lack of air circulation would not work for our receiver, so once again, I got my hole saw out and cut a couple of holes in the back of the cabinet, directly behind the receiver. For power, I just borrowed one of the eleventy-billion USB power cubes that seems to be multiplying around the house and let them run 24/7. I suppose I could use a thermostatically controlled power supply or something, but I haven't gotten around to it.Now here's the kicker and the reason why I would buy these again without a second thought: I've been using these fans for probably 8 years now. Remember how I said I didn't have them thermostatically controlled? They've been going practically all day every day over that time. No noise, no slowing down, no problems at all, and all for less than $15. If they up and died on me tomorrow, I'd be on revain ordering up the exact same fans to replace them, I'm that happy with them. Outstanding value and performance like this is hard to beat.