If you're looking for a replacement 80mm 12 volt computer fan for power supplies or other equipment needed in quiet locations, this is the fan:
Nexus makes the model SP802512L-03
They are available from:
http://www.coolerguys.com and from www.Amazon.com for about US$9.00 to $12.00
http://www.nexustek.nl http://www.pctoys.com http://www.heatsinkfactory.com http://www.performance-pcs.com
Caution! When testing this fan, keep your fingers out. You can't see hear or feel it run so you will be tempted to stick your fingers into the blades sand possibly break a fin.