There are standard size as 287 x 287mm, 387 x 387mm ladder truss, triangle truss, and square truss. The length can be 0. 5 - 4. 0m. According to the loading capacity, it can be classified light duty and medium duty, and both can be made of Φ50mm as main tube. The medium duty, made of Φ30mm, as inside tube, the light-duty, made of Φ20mm as inside tube. So the medium duty loading capability is better than light-duty.