Galvanized steel with riveted and soldered or welded seams with smooth interiors for quiet, efficient airflow, and large and small ends to facilitate lapping joints. Angle flanges can be furnished for field bolting. Standard pipe is made in 4" to 60" diameters from 20 to 12 gauge, in 3' sections up to 11" in diameter and in 4' sections for 12" diameters and above. All pipe is priced per customer's specifications and is also made to order in custom sizes and materials, including Mild Steel and Stainless. Larger sizes up to 3/16" thickness.