... noise, big flow volume, stable operation, rot durable. The roof blower ( blower , roof fan ):Features: light, low noise, big flow volume, stable operation ... and metallurgy factory, etc.Specifications: DWT series low noise roof blower including DWT-mode, DWT- mode, DWT- mode and DWT- mode ... :Ø280~2400mm,volume:1380~220000 m3/h,pressure150~1000Pa. roof blower ( blower , roof fan )