This document specifies the tolerances on form and dimensions of the following: —     wrought aluminium and aluminium alloy extruded round tubes, having diameters from 13 mm up to 450 mm. —     wrought aluminium and aluminium alloy extruded square, rectangular and hexagonal tubes, having circumscribing circle up to 350 mm in diameter. This document is applicable to extruded round, square, rectangular and hexagonal tubes. Four-digit numerical designations are in line with the Registration of International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys (known as "Teal sheets").[1]