There are standard size as 287*287mm, 387*387mm ladder truss, Triangular truss, square truss, The length can be 0.5-4.0m, According to the loading capacity, it can be classify light -duty, mediumduty, both, can be made of diameter 50mm as main tube. The mediumduty made of diameter 30mm as inside tube. The light-duty made of diameter 20mm as inside tube.