This Heavy Duty 12" x 18" Box Truss is manufactured with schedule 40, 1.9" OD x 0.145" wall main chords and 1.05" OD x 0.125" wall diagonal bracing. All components are 6061-T6 aluminum tubing and 5/8" grade 8 bolts are supplied for assembly of the truss elements. It can be used to construct a grid when combined with the matching corner blocks.