The SPT model is structurally very strong with a center post made of 6 inch square tube. The main seat arms are 3 1/2 inch O.D. pipe and seat and top supports are 2 3/8 inch O.D. pipe. Frame is hot dip Galvanized after fabrication for best protection. Support arms are secured against vandalism by using 1/2 inch round head carriage bolts with nuts hidden and inaccessible inside the center post. In-ground is standard on single post tables. It Extends approximately 20 inch into a concrete poured base.