310S Stainless Steel Rectangle Tube has internal and external radius corners, with a protruding interior weld seam. Stainless Rectangle Tube is ideal for all structural applications where greater strength and superior corrosion resistance is required. Having a durable mill finish Stainless Rectangle Tube is widely used for all types of fabrication projects that are exposed to the elements - chemical, acidic, fresh water, and salt water environments. Some sizes are available with a 180 grit polish.