COLORBOND® steel Double-Sided is pre-painted steel with colour on both the top and underside. The underside has a high-gloss finish. 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). Minimum coating mass is AM100 (100g/m2). The base metal thickness (BMT) is 0.42mm or 0.48mm, depending on the product.