Silent PC fans

Ordered at AliExpress:
Lonyo PC Cooling Fan 12cm, brushless,

Dimensions: 120x120x25 mm
Design: Nine Sickle Leaves

Speed: 1100 RPM ±10%
Rated Voltage: DC 12V
Rated Current: 0.25A
Air Flow: 88 cfm
Noise: 20 dBA
Bearing type: Hydraulic
Connector: 3 or 4-Pin (2 pin used) - GND, 12V, Tach (rpm signal)
Life: 50.000 hours

Price: €12,50 / 2 pcs

I Tested RPM with Arduino:

12V - 1220 rpm

  9V - 1100 rpm

These fans are really quiet and give plenty of air flow.

Note: DIY Fancontroller: YouTube with 10k variable resistor and LM319 NPN Transistor