SF adopt special twisted blade design and flange flanging casing, whiich makes the noise lower and the air volume larger. The advanced painting process maintains surface smooth and beautiful. The series are featured by good performance, asy maintenance and used to transport air in workshop storage and places of recreation and other places. But these places should not contain flammale, explosive and corrosive gases, with a temperature no higher than 50 temperature. We have a lot of size of this kinds of fans.