1.Dimensions: Choice 41 x 41mm or 41 x 21mm 2.Lengths: Either 6M or 3 Metre Lengths 3.Style: Plain or Slotted Welded Steel Channel1)Size:41mm*21mm or 41mm*41mm back to back 41*41mm, 41*62mm,41*82mm,and so on2)Thickness:1.5mm, 1.8mm,1.9mm,2.0mm, 2.3mm,2.5mm ,2.7mm,3)Length:10 and 20 feet(3m,5.8m,6m ),special length are available upon request4)Holes:28*14mm,18*9mm,30*33mm etc5)Material :Carbon ...