AC InfinityMULTIFAN S7, Quiet Dual 120mm USB Fan, UL-Certified for Receiver DVR PlayStation Xbox Computer Cabinet Cooling

I bought these fans to cool my 700 watt surround sound system receiver that produces a lot of heat, so this review will be in depth and thorough. I ran two tests, the first with the receiver on top of the cabinet with open airflow, and the second inside the cabinet with closed airflow. I will also use an Infrared Laser thermometer to test temperatures inside of the receiver, from whence the heat is created and is at its hottest, especially on heat sinks and chips. My receiver is vented all over the top and bottom so peeking through isn't a problem.Test 1 - For test one the receiver will sit on top of the cabinet with open airflow. Since heat rises i have placed the fans on top of the receiver blowing upwards since there is no room underneath it and the weight of it will crush these two fans even though they are built pretty tough. With no fans my receiver idles around 150 F and at loud volume rises to 200ish F. That's just too much. Now i throw in the dual AC Infinity fans and start them out at low and move to medium and them high, taking temperatures as i go. On low speed, temperatures only came down to about 190 F, so still no cigar. On medium i got more result, down to 150 F, which is what i call the green zone. And on high, the temps came down to a whopping 98 F. Also, the only time i could hear noise from the fans was on high, so they are indeed quiet and powerful. The static pressure wasn't bad either, i have more powerful inside my PC but you can actually feel some air coming from these.Test 2 - For test two the receiver went inside the cabinet. I expected results to be worse in there due to the restriction of airflow but i was surprised. With the fans in the same place i started with low speed and measured 180 F inside the receiver. I'm guessing the fans get better directional airflow inside a cabinet without things like a ceiling fan interfering. Medium speed is where it got interesting, 125 F is what i measured from the laser. And then on high speed, i measured a chilling 88 F on the heat sink around the power supply inside the receiver, usually the hottest spot i can point at with the laser. Very impeccable results. The only thing is that after 30 - 45 minutes there is a build up of heat inside my entertainment cabinet, so must leave the glass door open for heat to escape while in use, but now i wont haft to worry about it catching fire.Conclusion - Totally awesome fans. Their performance is impeccable. Also, they construction is very very solid and nice. If my reciever was just a little smaller and lighter i could sit it on top of these and have them blowing from the bottom. The grills are child finger proof and easy to clean, and the wiring and switch has nice thick cable and strong plastic. And the extra female USB port is great for when you need that third fan, or another set of AC Infinity fans. The only thing i could see improving here, other than the obvious like RPM's and static pressure, is making a true AC wall jack powered version of these with the double - triple - quadruple fan setup for devices that don't have USB ports. I know AC Inf. makes AC powered fans but they're all singles. Need multiples! I would highly recommend tese fans to anyone who needs extra cooling for their non-desktop PC electronic devices. You wont be disappointed.

2/11/2021 UPDATE! Just reordered another S7 pair of fans! Andy, I have never met you, but I sure like these quiet fans and continue to recommend these!I have three of these fans in a media closet that is about the size of a tall refrigerator. Inside on shelves I have a high-powered AV receiver, a BluRay player, a Cable TV DVR, and other stuff that is producing an amazing amount of heat. When we built the house the wife wanted all AV equipment hidden, and as an Audiophile I wanted to be able to see what I want to see and hear what I want to hear in the Home theater seating area, but without any extraneous noise.Solution: I bought this item, and set two fans on top of the AV Receiver and a third identical fan on top of the cable box/DVR. Closed the door and waited an hour. Heat load dropped in half. I did not want to just move a hot air around in this large closet, so there is a passive vent installed in the sealing of the closet .... just a simple louvered floor vent like people have in their homes for floor heat. I just waited until the wife unit was out of the house and used one of her good steak knives to saw a hole in the drywall ceiling a drop this Lower cheap floor vent in:) Vacuum the mess up and done. These fans have been running flawlessly for two years now - and my wife, who could hear a mouse fart, has never noticed them.Quality/overall impression: Frankly, I thought these were two cheap to be really durable, but I bought them because at the time they were one of the few USB fan setups with a speed controller, no fan-boi disco light show LEDs, and with a CEC rating. The fans are very quiet, well-made, and have nice rubber anti-vibration feet.I was nervous about leaving cheap fans on 24-7 because the last thing I want to do is have a house fire because the units were wired up by orphaned slave labor recruited from a deplorable third world slum. But those fears were immediately put out of mind when I opened the box upon receipt. Beautiful packing, high quality wiring and fan construction.I am back on their site today reordering a second set to place on my desktop next to my computer workstation. I have a couple of good friends who work designing high end consumer electronics - the really pricy stuff. Both techs told me that placing a good quality cooling fan on an AV receiver can add several years working lifetime to such units.Therefore, I highly recommend these AC Infinity products. Just buy the dual fan setup, set the speed controller wherever you are comfortable and forget about them! (slower is a little quieter, but even on high these were very acceptable for my application) And like I said, I am back today repurchasing another set, which I should have done long ago:) Heat kills electronics. And if you are checking out cooling fans, you already know that stereos, AV equipment and computer gear can generate enough heat to slowly nuke your gear...Next possible project for these.... We have a couple of large walk in closets, which we keep the doors closed on because our ever-curious weenie dogs like to curl up in when we are not home. Anyway, I put the old computer fans, which were too noisy, in the closets to keep the air circulating and not smelling musty when we have been gone for awhile. One of these small fans would be much quieter, and would be strong enough to push all the air it needs to under the closet door to keep things smelling fresh in there - even after we have returned from a couple weeks vacation.