ASTM A475 Class B galvanized steel strand, 1x7, 6mm to 10mm, certified to a named standard rather than a general description. When a specification names ASTM A475 Class B, it is naming a coating mass and a set of mechanical requirements, not just a colour. Class B sits between the standard Class A and the extra heavy Class C, and it is the class most often specified for outdoor and marine-adjacent work where Class A has proved too thin but Class C is not justified on cost.