Circle truss: 1, had passed TUV certificate 2, convenient to transport and assembly. 3, we have a professional technical The circle truss connector by the spigot , the circle truss which can make difference in diameter the aluminium square spigot truss /spigot truss/stage truss/light truss/project truss which is connector by the spigot , it is very popular at market , Especial at Europe market , ...