Set of strings for acoustic guitar. Phosphor bronze strings are made of quality steel that contains carbon. The individual strings are then wrapped with phosphor bronze and further coated with a thin layer of polymer, which extends the life of the string up to three times. This micro-coating not only extends the life of the strings, but also sustain, tone and surrounds the overall sound. The phosphor-bronze material is warmer and more acoustic than bronze. In addition, the thinnest "e1" string is included in each set for free.