Detailed Product Description content Roof fan:Dia.300mm~1120mm.Volume:3300~53000m3/h, ... 0.37kw~5.5kw,Voltage:380V/440V/OtherCentrifugal Fan ordinary roof WT4-85-11 series uses and conditions of use: ... 85 DbA noise indicators. Low noise centrifugal fan DW3 roof-88-11, DW4-75-11 series uses and conditions ... DbA small noise indicators. Ex low noise centrifugal fan BDW3 roof-88-11, DW4-75-11 Series: 1. Use ...