SQ-C4.0-90 - 4.0 meter (13.12')The SQ C4. 0 90 is a 4. 0 meter (13. 12') diameter 12'' box truss circle. It is made from the same high quality 6082 T6 aluminum as the rest of our 12'' truss for high strength and a low self weight. The circle is comprised of four 90 arcs that can be purchased separately for custom designs or arch ways (please call for details). Features: 4. 0m circle (13. 12') 12'' aluminum box truss 2'' O. D. main tube 2MM (. 08'') wall thickness 4 x 90 arcs