€¢ All aluminum duct is ideal for applications where code requires an all aluminum product €¢ Totally non combustible with a maximum operating temperature of 435 deg F €¢ The UL 2158A listed and marked class 0 version is thicker than the standard duct and incorporates new technology that allows for easy rotation and more durable handling >> The semi-rigid aluminum duct is ideal when all aluminum duct is required by code in some gas and electric dryer applications. This duct is totally non-combustible with a maximum operating temperature of 435 deg F."