TwinkleBay 40x28mm Cooling Fan, Replacement for 4028 Maglev Cooling Fan, 40x40x28mm with 3 Pins 3 Wires Connector DC 12V (2 Pack)

I purchased this product to help with cooling one of my larger telescopes to increase the amount of airflow passing by the primary mirror helping it to reach equilibrium with the surrounding outside airA great product, and works very well. Very quiet, and so far I haven’t had any issues. We’ll see how well they hold up over the course of a year

These things were horribly out of balance and vibrate so much I couldn't stand it for 5 minutes. Ordered some Artic brand (5 pack) to try and WOW, total quiet, just a whir.Avoid these and pay a bit more for much better fans.I had to shorten cord and remove plug or id return these.

Works great

The two fans I received work fine (i.e., they move air around) but there doesn't appear to be any RPM signal. I don't have an oscilloscope to check if the signal is completely missing or if it is slightly out of spec (e.g., too weak, too noisy) but my motherboard is unable to recognize the signal (if present). I tried several different fan headers which I know to be good and none were giving me any RPM feedback.

These can be felt from across a room. They can be quite loud when secured to a box due to resonance. They are quiet enough on their own. My thermo peltier project failed so I'm using one as a desk fan. They move some air for sure.

Ordered 2 in January. One died by April after very little use (estimated 72 hours total time).

Not sure what the point of advertising specs, and repeating them as answers to questions. These fans pull .3a, that's 3.6w. There no where near the rated cfm, not even close. They're quiet, but that's about it. A quick test on the bench shows they specs are made up.

Just needed it to cool the cpu, and it saved all the rest for a fraction or replacement cost. Great part to have on standby "just in case" too!