Aluminum Round Tube 6063, Aluminum, 6063, T52, Round Tube, 12 in Overall Length, Outside Diameter 4 in, Inside Diameter 3.624 in, 0.188 in Wall Thickness, Fabrication Extruded, Heat Treatable Yes, Mechanical Finish Mill, Yield Strength 31,000 psi, Tensile Strength 35,000 psi, 73 Brinell Hardness, Includes Material Certificate Yes, Standards ASTM B221, System of Measurement Inch