Square Tubes: Structural Tubes, also known as hollow sections, are used as a structural element in buildings, bridges and other structures, and in a wide variety of manufactured products. It’s produced in round, square and rectangular shapes in a broad range of sizes and gauges. Square Tube, similar to round tube, has efficient shape for multiple-axis loading as it has uniform geometry along two or more cross-sectional axes, and thus uniform strength characteristics. This makes it good choice for columns. It also has excellent resistance to torsion.