System1 Designs 3" Inch Stainless Steel Mandrel High Quality 15 Degree Bend Angles Turbo Exhaust System Fabrication Shops Piping We have many combinations of radius and tube diameter to suit professional exhaust builders, fab shops. We are continuously adding to our capabilities and inventory. We offer mandrel bent 304 stainless steel in various diameters and bend angles to help with your custom exhaust and turbo system fabrication. Features: 304 Stainless Steel. 16 Gauge. Average Length = 13". 15 Degree Bend. 3 inch Diameter. Raw Finish.