U-Channel, Corrosion Resistant, Aluminum, Alloy Type 6063, Leg Length 1", Base Width 4", Wall Thickness 0.125", Length 8 ft., Mill Finish, T52 Temper, Leg Length Tolerance +/-0.012", Base Width Tolerance +/-0.034", Wall Thickness Tolerance +/-0.007", Length Tolerance +/-1.000", Tensile Strength (PSI) 27, 000, Typical Yield Strength (PSI) 21, 000, Typical Hardness 60, Hardness Scale BHN, Standards ASTMB221