Check the listing for details. 10 Pack D'Addario EJ17-10P Medium Acoustic Guitar Strings Phosphor Bronze 13-56. Condition: New. Listed at 71.99 USD. EJ17-10P 10 Sets D'Addario Acoustic Guitar Strings D'Addario EJ17 Medium Phosphor Bronze Acoustic Guitar Strings (13-56) D'Addario's most popular acoustic medium set, EJ17 delivers the ideal balance of volume, projection and comfortable playability. Phosphor Bronze was introduced to string making by D'Addario in 1974 and has become synonymous with warm, bright, and well balanced acoustic tone. D'Addario Phosphor Bronze strings are precision wound with corrosion resistant phosphor bronze onto a carefully drawn, hexagonally shaped, high carbon steel core. The result is long lasting, bright sounding tone with excellent intonation.Made in the U.S.A. for the highest quality and performance EJ17 String Gauges: Plain Steel .013, .017, Phosphor Bronze Wound .026, .035, .045, .056