The high-quality NB-EKA Plus II drive and the almost noiseless NB-NanoSLI bearings guarantee operating noise levels which are particularly low over the long term - both equipment features which until now have only been used as part of the costlier Multiframe Reference series.In addition to the tasteful design in matte black and mirror finish, the BlackSilentPro fans are equipped with an individually extendable cable management system and an NB-Silentframe silicone seal and installation material for vibration-free assembly without tools. Specification:- Dimensions: 92x92x25mm- Noise Level: 20dbA- RPM: 1800rpm