It is bolt aluminum truss, Generally it is adoptedФ50*3mm aluminum tube as main material (Main tube could be also be thicker or strenghen tube). there are bothe aluminum quarate tube and alumuinum bord as joint,but heri functions are the same , they all implement the connecting among aluminum trusses . we munt with 8.8 degree's bolts of hight intensity with 55mm thicker gasket. we equip with manual sleeve on the installment tools .