Hercules offers 8', 5' and 4' sections of rectangular ductwork. Rectangular ductwork is used in the main supply of heating and cooling systems and return ducts in addition to venting bath fans and range hoods. Rectangular ducts are usually sold in half sections; two pieces need to be ordered for a full duct section. All ductwork is made to conform with SMACNA standards. Hercules rectangular ductwork has unique cross break across the ductwork to reduce popping sounds in residential applications.