... , best prices and good quality Different choices: round /rectangular /square pipes Specifications:1) Round pipes-Outside diameter (unit: mm)8 ... ,9.5,11,12,12.7,14.5,15.9,17,18,19,20,22 ... 102,114,133,141,159,2192) Square pipe-Outside diameter (unit: mm)10×10,12×12,15×15,17×17,18×18, ... pipes: Outside dimensions (mm)20×10,23×11,24×12,25×13,30×30,36×36,38×38,40×40 ...