COLORBOND® Ultra steel is pre-painted steel for severe coastal or industrial environments. The painting complies with AS/NZS 2728, and the steel base is an aluminium/zinc/magnesium alloy coated steel that complies with AS/NZS 1397. Minimum yield strength is G550 (550 MPa) or G300 (300 MPa), depending on the product. Minimum coating mass is AM150 (150g/m2). The base metal thickness (BMT) is 0.42mm, 0.48mm or 0.60mm depending on the product.