Lambro Industries Flexible Semi-Rigid 4 inch x 8 foot UL 2158A Clothes Dryer Transition Duct KitThe Lambro flexible semi rigid 4 inch x 8 foot UL 2158A clothes dryer transition duct kit is ideal for venting a clothes dryer to the outside. This kit is used for clothes dryer exhaust venting applications that require moist air and humidity from exiting the home. The corrugations throughout the duct prevents collapsing and allows for easily bending the duct when needed. The class 0 aluminum is corrosion resistant non combustible and fire resistant