black iron wire (materials for construction) 1.Packing: in coil, by spool, cut into sizes for ... /bundle 2.T/S: 500~980 N black iron wire (materials for construction) Diameter: BWG16, 18#, 19#, 20#, 22#, are the most ... to rust. Mainly used for binding materials, Daily use and using as binding wire for construction,.wire gauge sizeSWG(mm)BWG(mm ...