Vent-Axia Silent VASF100B 4"/100m Axial Bathroom and Toilet Fan - 446658 Featuring a high efficiency motor and a 100mm, 4 inch, forward curved, seven blade impeller, the Vent Axia Silent Fan delivers exceptional performance at incredibly low noise levels: Whispering away at 26dB(A) on high setting and only 14dB(A) on low speed, it is now officially the quietest extractor fan available. The 446658 VASF100B offers two fan motor speeds for precise ventilation specific to the individual installation.