Summary: Used for replacement on removable (swappable) disk drive enclosures. 2 for each. Exactly what we were looking for. Strong air movement and very quiet. Used to use one, not so quiet, fan per enclosure. Now we use 2 of these with less noise than before.
Summary: So quiet that I couldn't believe it was actually spinning when I first hooked it up. Must spin a little slower than the original fan because the CPU temp went up by a couple degrees, but no big deal... this thing is amazing.
Summary: Orignially I bought this for usb driving. Unfortunately the starting voltage(the fan starts running) is 6.4volt. But I can't blame it. It is very quite, flow is low too. Generally it is a good product. Just pay attention if you don't use it under 12volt, 6.4volt is the minimum voltage.
Summary: I bought this to replace the cheap fan that was OEM on my E350M1 motherboard, which sounded like a group of staplers took flight whenever it spun faster than 2000rpm (which it did often). This is almost completely silent, I have to stand within a 1-2 ft radius to hear it. Doesn't move a ton of air, but it keeps my CPU cool enough.
Summary: I got the Scythe Mini KAZE 40mm Fan (SY124010L) to replace a very noisy fan on the PSU from a Cooler Master Elite 100. I had to do some soldering but the noise is gone. This fan move the same amount of air and it does it very quite..