Corrosion Resistant Rectangular Tubing, Aluminum, Alloy Type 6063, 2 in x 4 in Outside Rectangle Size, 1-3/4 in x 3-3/4 in Inside Rectangle Size, Wall Thickness 0.125 in, Wall Thickness Tolerance +/-0.015 in, Length 3 ft, Length Tolerance +/-2.000 in, Outside Tolerance Standard, Mill Finish, T52 Temper, Tensile Strength 27,000 psi, Typical Yield Strength 21,000 psi, Typical Hardness 60, BHN Hardness Scale, Standards ASTMB221 Package of 4.