Fan gaskets are electrical components designed to reduce the vibration between a fan and a chassis. They do this by maintaining a seal between the fan and the housing to prevent air leakage.
Fan gaskets help to seal the small gap between the fan and the enclosure chassis. This helps to reduce airflow 'feedback" and therefore loss of air pressure, ultimately improving the fan's efficiency. Without a fan gasket, the rotating action of the fan would transmit vibration into the case housing and case chassis.
Fan gaskets come in a broad variety of options and are suitable for a vast majority of fans and case designs. They're provided in different dimensions suitable to match the hole spacings in fans.
While some fan gaskets are self-adhesive, others will have fan mounting machine screws and washers to ensure a secure fit. The screws feature a threaded design, further helping to prevent the transmission and amplification of vibrations through to the chassis.