80/20 Bronze, often referred to as brass, is the original acoustic string alloy from the 1930s. Strings made from this material are very popular for recordings due to their strong, clear, and defined sound, and they remain highly sought after by traditionalists and vintage enthusiasts. D'Addario acoustic strings feature an outer material wound around a hexagonal carbon steel core, resulting in durability, brilliant tone, and excellent intonation. Extra bright sound with deep and projecting bass. Gauge: .010 .014 .023 .030 .039 .047.