Noiseblocker NB-Multiframe M12-S1 120mmx25mm Ultra Silent Fan Unique, multipart vibration-free chassis with integrated structure-borne sound absorbers and glass fibre-reinforced frame Reverse pole and overload protection, restart function, extremely failsafe Extremely low start voltage Extremely low-noise and long-life NB-NanoSLI bearings Includes assembly material and additional sealing/ decoupling frame; 6-year warranty