The Lambro flexible semi-rigid 4 in x 8 ft duct is ideal for general-purpose venting applications including bathroom fan and kitchen range hood exhausting. 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 with a maximum operating temperature of 482°F. Check local building codes prior to installation. Do not use for clothes dryer installations (UL 2158A duct must be used).