Chicago's Direct Drive Fan is available as a SQBD with backwardly inclined blades in addition to the airfoil bladed SQAD. With the choice of two types of wheels application duty can be matched precisely. Also, the different performance characteristics of the two wheels allow for a wider performance range at standard synchronous motor speeds. The compact SQAD/SQBD direct drive fans are used in diverse OEM applications, from packaged forced air and dust collectors to pressurizing and aeration installations.