80/20 Bronze, commonly referred to as brass, is the original acoustic string alloy selected by John D'Addario Sr. and John D'Angelico in the 1930s. 80/20 bronze strings are popular for recordings due to their clear, deep, and penetrating tone, appealing to many traditionalists and vintage enthusiasts because of their historical significance. All D'Addario acoustic strings are wound on a hexagonal-shaped core made of high-carbon steel, resulting in a durable, bright sound with excellent intonation. D'Addario offers a complete range of acoustic guitar strings for all your replacement or customization needs. .047 gauge bronze-wound acoustic guitar string. Extra bright sound combined with deep and penetrating bass. Perfect as a replacement string or for creating custom sets. Made in the USA for the highest quality and performance.