These Rubber work well with the standard fan my Fantec R2750 and make this a little quieter. Did this Rubber but in addition to Noiseblocker BlackSilentFan XM1 fan (40x40x10) use. Unfortunately, the NB has XM1 narrower holes, so I still need either thinner or Ruber the holes "drill out" something greater needs. So problem is not limited to this Rubbern ...