Argon Forty Mini Fan HAT with Built-in Heatsink | ON-Off Switch for The Heatsink Fan | Fully Controllable PWM HAT | 2 Pieces of Fan per Pack

Needed a new fan for my Argon raspberry pi case, and these fit, although slimmer they work fine.

Installation was simple. You just push it down onto the GPIO pins. The manual mentioned using a silicone thermal pad, but I just used some Arctic Silver 5 I had on hand.There is a switch on the side of the unit that gives you three options. "On" (fan is always on), "Off," and "PWM" (fan comes on automatically at a certain temp). I set it to PWM, booted up the Pi, and edited boot.cfg according to the instructions so that the fan will come on automatically at 55°C.Then, I ran a stress test and watched the temperature and fan to make sure it worked. The starting temp was 45°C. As the stress test ran, the temp climbed. Right when it hit 55°C, the fan came on. The temp quickly dropped back down to 45°C. The stress test lasted about 10 minutes and the pattern was fairly consistent: temp would rise to 55°C, fan would come on, temp would drop, fan would go off, temp rises back to 55°C, fan comes back on, etc. There was no problem at all staying below 55°C.The fan does make noise. I wouldn't consider it "loud" but it is noticeable if you are nearby. But, my estimation is the sound is caused by moving a lot of air rather than the unit being low quality. I don't expect the sound to be a problem unless you have the Pi very close to you and/or your hearing is very sensitive.Overall, I would recommend this product. Excellent value since you get 2 for 10 bucks. If the unit craps out or any other problems arise, I will update this review.

I really like this little heatsink fan combo for the RPi 4. It really keeps the temps down on the CPU. There is a selector switch on one side that allows you to have the fan On/Off or PWM. To set PWM, there are instructions included. The only issue I have with it, is that the copper heatsink makes it so you can't place a separate heatsink on the RAM module. This could be a deal breaker for many out there. For an example on temperature, I setup my Pi4 to mine monero for kicks and giggles. It's a good test because it pins the CPU at 100% all of the time. With this cooler, it is between 49 and 51.6....that's in real degrees. Celsius! 😉Without the heatsink, Idle temps are in the low to mid 40's, so not too shabby.

Fits perfectly with the Poly+ case, instructions are clear on how to set up PWM (reboot after making the changes). Super quiet as well. My temps dropped from 70c to 47c

First off, I only own one pi, so the two fans is redundant at the moment, though it gives me an excuse to buy another. Second, as the product is a fan, and not a super premium one, there is a good level of sound associated with it, but not enough to bother me, personally.Third, Product seemed to prevent system start up when not pushed down all the way on the pins, although the instructions clearly indicate to do so, therefore no stars docked for that.Finally, I would have liked to have the heatsink that hovers over the ram chip to sit higher up so that a separate heatsink could be used with said chip, but what are you going to do. And, additionally, it turns out that I rarely use the pi in any capacity where I'd actually need the fan, so there's that.