The document provides size ranges for square hollow section (SHS) steel tubes. It lists various dimensions including width, thickness, and coding for square hollow sections produced through different manufacturing methods, including painted, galvanized, and electric resistance welded (ERW) tubes. The sections can be produced in sizes ranging from 13x13mm to 300x300mm in width and thickness and in materials including steel, stainless steel, and aluminum. Tolerances for ERW tubes are also provided.