IS2 PCS 50mm 12V Cooling Fan,Icstation 0.08A 5010 5012 DC Silent Brushless Long Life Computer Fan for 3D Printer PC Computer Case Fan, 4200 RPM High 11.89 CFM

This is a pretty good fan for the price! Fairly quiet, at least more quiet than the fans I've been getting through Amazon, and moves a lot of air. Comes with a fairly common JST-XH connector pre-installed so I didn't have to spend too much time trying to figure out how I want to connect it since I always have a bunch of those connectors on hand. What's better, you get two for the price! I'm impressed

Same size as old fans. Fit just fine. Had to swap wire polarity in connector. Easy to do with a push pin.

My security camera system's vcr had a broken cooling fan. The fan was very small (2.5" x .5") and hard to find a replacement fan which would fit in the small space it had to go. These fans were a little smaller than the original but were easy to install. The fan is also super quiet, better than the original. The connector socket on the fan plugged in perfectly. Also the price was very reasonable. I am very pleased with the replacement fan and would recommend this product.

Good value and fast delivery.

Update: I run this fan for 16 hours a day and in 67 days the bearing is now howling when it starts up. That's about 1,072 hours. Since this one and its twin both had the surging RPM issue, I didn't even bother with the other one. Going for a name brand one next. (Fixed some typos in the original review below)Original Review:I bought these fans to replace the 20-year-old Cooler Master fan in a legacy desktop. Before installing it, I tested it with a 12V battery to see how loud it would be and how much air it moves.The fan is whisper quiet - the tradeoff is it moves very little air but it's enough to cool a Pentium 3. The thing that is disturbing however, when I was testing it on battery - the fan revs up and down quite significantly on it's own. This is not intended and is a problem in the motor circuitry. Since it's going in a machine I take apart frequently I am not terribly concerned but I certainly doubt this will last the same 20 years that the old cooler master fan did.The pack did come with two fans and indeed they both exhibit this poor speed control behavior even when on a steady power supply. Could be a bad batch or this could turn out to have very little effect on their service life - time will tell.