D'Addario EJ13 Custom Light 11-52 80/20 Bronze Acoustic Guitar Strings D'Addario Strings 80/20 Bronze are D'Addario's brightest acoustic strings, made to give your guitar an unparalleled shine. These bold sounding strings were developed by John D'Addario Sr. and guitar maker John D'Angelico in the 1930s, and have been beloved for their sparkling, trebly tone ever since. Made with a high carbon steel core and 80/20 Bronze wrap wire, 80/20 acoustic strings offer remarkable depth, along with rich, bright harmonics, and powerful projection. These 11-52 Custom Light gauge strings have slightly more volume and projection than Extra Light, while still being easy to play.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 hold a crisp, deep and projecting tone and appeal to many vintage enthusiasts for their historical significance