The Lambro flexible semi-rigid 4 inch x 8 foot 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).