ITEM NAME:6pcs/set Acoustic Folk Guitar Strings Steel Core Copper Wire Wound Tens JtJ Bj.1set(6pcs) x Folk Guitar Strings. 3rd, 4th, 5th and 6th strings are adopt high-carbon steel hexagonal core, 99% pure copper of wire wound,strong tightness. Material(3rd, 4th, 5th and 6th strings): High-carbon Steel (inside) / Copper (outside).