Imperial 4 Inch x 6 Foot quick connect hook-up semi-rigid dryer duct. All-metal UL (Underwriters Laboratories) approved pre-assembled kit features a 6 Foot in length UL listed semi-rigid clothes dryer transition duct. Two quick-fit connector fittings allow the duct to connect to the dryer exhaust port and exhaust vent hood without clamps. No tools are required.