Fantech FKD Inline mixed flow duct fans are designed to bridge the transition between centrifugal and axial by combining the high flow of axial designs with the higher pressure, non-overloading characteristics of backward curved impellers. With FKD Series fans, system balancing is achieved by measuring the system flow or pressure and adjusting the fan performance by "dialing in" or setting the fan speed using inexpensive solid state speed controls, transformers or VFD's. Direct drive eliminates the need for continuous belt alignment, tension adjustment and ongoing maintenance.