... ) Round PipeOuter Diameter: 6mm, 8mm, 9.5mm, 10mm, 11mm, 12mm, 12.7mm, 13mm, 14.5mm, 15.9mm, 17.2mm, 17mm, 18mm ... , 152.4mm, 159mm, 168mm, 203mm, 219mm2) Square PipeSize: 10X10mm, 12X12mm, 12.7X12.7mm, 15X15mm, 17X17mm, 18X18mm, 19X19mm, 20X20mm, 22X22mm, 23X23mm, 24X24mm ... , Staircase, Door, Window, Balcony, Fence, Bench, Furniture, etc. Stainless Steel Heat Exchanger Tube