... ,different size 4,have a long history bule cover truss,roof truss,aluminum truss Material size details: 150*150mm,200 * 200mm,300*300mm, ... 400*400mm ,300*400mm etc.screw to connect the standard aluminum ... alloyFrame :4,3,2Type: 4,3,2.Material: Aluminum 606,160,636,082Head (diameter * ...