... flow coefficient on the basis of the fans, specification, distribute every sectional character-istiv speed & length of the vanes, the fans have low noixe ... dynamic balance adjustment & over speed test. Therefore, the fans als have the features of good-anticorrosion, anti-swing, vi-bration ... resistance, shock resistance, stable running and safe reliable.The fans can be used with 380V/220V, 50 HZ or ...