shutter:with a centrifugal system which can ensure the shutter open and close automatically,and makes it dustproof ,waterproof.Motor:the high efficient and energy-saving motor with protection grade:IP55,insulation class:F.Belt: Automatic tensioner to prevent the belt loosing and droping off.技术参数model Diameter blades(mm) Air volume power Outer size(mm) voltage frenquencyXLXS-1000 1000 35000 m3/h 0.75KW 1100*1100*400 380V 50HZXLXS-1250 1250 42000 m3/h 1.1KW 1380*1380*400 380V 50HZXLXS-1400 1400 55800m3/h 1.5KW 1536*1536*400 380V 50HZ/p>