GeeekPi Raspberry Pi 4B GPIO Expansion Board with Dual Cooling Fans DC 5V with LED, Raspberry Pi 4B Heatsink Kit for Raspberry Pi 4 Model B/Raspberry Pi 3B+/3B/Raspberry Pi 2B/Raspberry Pi Zero

Seems like a good cooling solution, particularly for a niche need like mine. I have a RP 4 and an RP 3B+ rackmounted for network services and have been looking for a good cooling solution. With the RTC hat, and all of the cables in the rack, had limited success. Last solution I tried only sat on thermal pads without any pressure, subject to fall off with the slightest bump, or moving the rack. My concern here was I'd have to be creative mounting to the rackmount solution. Turned out, the stand offs had the same threads, so installation was a breeze. Bonus, the LED does add some glam to an otherwise geeky but boring home project.PROS:- Easily mounts to the PI, looks like the GPIO could also be strong enough to hold the fans by itself.- Works (at least with mine) rack mounted solution.- Extends GPIO so hats can be used OVER the fans- Fans seem relatively quiet (in a server rack)- Though not necessary, light is a nice touch- Works with RP 4 and RP 3, suspect others as well.CONNS- Only real gripe if have is you cannot invert the fans with the included hardware. Direction is from the PI up through the fans. My setup, I have huge intake fans ABOVE the PI's feeding the network gear. Would have liked to take advantage of that air stream. I'll have to get some nylon screws and nuts at Lowe's at some point to invert the fans.

This has some great positive points:- Very effective cooling. Typically my Raspberry Pi 4 is around 30 deg C at most. I haven't done any sustained heavy workloads but no doubt this will do a good job regardless.- Quiet enough. You can hear the fans, but it's totally fine for me.- Easy access to the full set of GPIO pins. You don't need to use two pins for the fan like others do, which is very helpful if I'm using a 40-pin cable to a breadboard for bigger projects. The pins are clearly labeled for small projects where I'm just connecting directly to the fan HAT pins.- Complete kit at a great price. It has everything you need including mounting hardware and aluminum heat sinks.There are a couple of negative items:- The switches are horizontal and will interfere with some cases. Depending on your case you might consider another fan HAT with vertically mounted switches.- Operating the switches reboots the Raspberry Pi. This is a dealbreaker for me, and this is why I'm returning it. It reminds me of once I mistakenly briefly shorted my Raspberry Pi 3 when I first got it and it did the same thing. You'll lose any unsaved work, and I suspect it's not great for you Pi to do this on a regular basis. The manufacturer suggested the issue was that I wasn't using a good power supply, but I'm using a new CanaKit power supply that came with my new Raspberry Pi 4. I tried other power supplies and it did the same thing. I got a replacement of the same item from Amazon in case I received a defective one, but the replacement does the same thing.

Cools Pi 4B fine, but reboots Pi when fan is turned on or off using on-board switch. Using 3 amp power supply, so current capacity should be fine. Fans are very quiet when operating.

Mine resets the RasPi all the time when a switch is turned on or off. Other than that, it looks cool and works fine. I would suggest to the manufacturer better testing and add a circuit to protect against reset.

I’m giving this case 1 star. It went together easily enough. But after careful assembly the fans wouldn’t work