The following are the specifications of different kinds of square pipe:15*15-1000*1000pipes.Rectangular pipe:10*20-1000*800,wall thickness:0.6MM-28MM.Criterion for Implementation GB/T6728-2002,material:Q195,Q215,Q235,Q345B,20#.We can also produce special specification(such as special wall thickness or material)according to customers'requirement.