Crafted from our most revolutionary string innovation, XS Phosphor Bronze strings boast the longest lifespan among all D’Addario acoustic guitar strings. The XS coating enhances the longevity of our warm, well-balanced phosphor bronze strings, providing an exceptionally smooth feel. Our strings feature a NY Steel core, phosphor bronze wrap wire, and Fusion Twist technology, resulting in unmatched durability and superior tuning stability, along with a significantly extended lifespan.