... supports 1.Square tube comes in:1 1/2",1 3/4",2",2 1/4" ... on1"Centers 3.Length: 2.5ft 8ft 10f square steel post supportsSquare tube comes in: 1 1/2", 1 3/4", 2 ... ", 2 1/4", 2 1/2" - Available in 2.5ft, 3ft, 8ft, 10ft, 12ft, 14ft and any length ... according to your demand- Available in 12 and 14 gauge- ASTM designation A653- 7/16" Holes ...