Have been used so set for use with Synology. Have rubbers missing from back due to support in synology. Basically these are ready for as an example a DS918+. Only for one.
200mm 5V 5V PWM FLX PWM Chassis Fan Cooling Fan Ultra Quiet Compatible With Noctua NF A20(NF-A20 FLX)
Noctua NF-A9 FLX, Premium Quiet Fan, 3-Pin (92mm, Brown)
Noctua NF-A4x20 FLX, Premium Quiet Fan, 3-Pin (40x20mm, Brown)
Noctua NF-A4x20 FLX Computer Case Fan - Cooling Components (Computer Case, Fan, 4 cm, 3700 RPM, 5000 RPM, 4400 RPM)
Noctua NF-A8 FLX 80mm x 25mm Low Noise Premium PC Case Fan 2000 RPM, 16.1 dBA
Noctua NF-A6x25 FLX, Premium Quiet Fan, 3-Pin (60mm, Brown)
