This all inclusive all metal dryer hook up kit is truly the ultimate installation kit for both the contractor and consumer. This kit includes a 4 in x 8 ft UL 2158A listed and marked semi-rigid aluminum duct, two attached all metal heavy-duty elbows and two 4 in metal galvanized worm gear clamps. The semi-rigid duct is UL 2158A labeled and approved for safe dryer venting. It is thicker than our standard non UL duct and like all aluminum ducts is totally non-combustible. New manufacturing technologies incorporated into this duct also allow for easy rotation, adding durability during installation. The two metal elbows are flame-resistant for a safe and long lasting connection and are designed to achieve tight 0 to 90 deg turns.