square pipe(square tube) size:15*15*0.5mm-300*300*13.0mm Square tubes(square pipe, galvanized steel pipe) Used for transportation of gas &oil, water, line, bridging, steel structure, power plant, piling, high frequency pipe. Also can do galvanizing. Size range:15×15×0.5mm – 300×300×13.0mm 15×30×1.0mm -- 300×400×13.0mm Square tube(Square pipe, hot dipped galvanized hollow bar)