Galvanized 45 Degree sheet metal elbows are fully adjustable from straight to 45 degrees. . They are the perfect sheet metal fitting for going around tight corners and utilized for maintaining the best airflow for maximum efficiency in your HVAC duct system. They are manufactured from the highest quality 26 gauge galvanized sheet metal up to 12" or 24 gauge galvanized sheet metal from 14" to 24" and have one end crimped. Perfect for use with either flexible duct or sheet metal duct. They are also crimped on one end for you to easily fit into a pipe or any other sheet metal fitting of the same diameter. You can use this 45 degree elbow to make sharp angular or gradual turns in runs of duct. They are thicker than the HVAC parts bought at Home Depot, Lowes, Ace, or any other hardware store. Always rememer the lower the number in sheet metal = the thicker the metal it is. So dont settle for the thin stuff! Refer to this chart.