... American standard sizes available) Material: Carbon Steel used in bridge, Stair treadSurface Treatment: Hot-dipped Galvanized or black.Appearance of Surface ... used in the platform, corridor, bridge, well covers, stairs, fencing for petroleum, chemical, power plant, waste treatment plant, civil engineering projects ... /60/50G455/60/50G505/60/50G555/60/50G605/60/50 stair tread(manufacturer)