Fan Silencing grommets dampen vibration, so they lower the noise coming from PC cooling fans. 

You need 4 grommets per fan. Best used with #8 self tapping screws. Enlarge existing fan mounting holes with 1/4" drill bit.  Push fan screw through grommet.

Fan Silencing (set of 4)

an Silencing grommets dampen vibration, so they lower the noise coming from PC cooling fans. Sold in set of 4 per fan. Best used with #8 self tapping screws. Enlarge existing fan mounting holes with 1/4" drill bit.