Direct Drive and Belt Drive Centrifugal Inline Fans are widely used in square ducts as clean air boosters in both supply and exhaust systems where the installation of convetional blowers is impractical. Their compact design gives designers an excellent alternative to conventional blowers. Centrex Inliner fans can be installed either horizontally, vertically or at any angle determined by the duct work. Full size removable panels enable easy access to the fan interior.