D'Addario XTAPB1047-12 Phosphor Bronze 12-String Acoustic Coated Guitar Strings .010-.047D'Addario XT Acoustic Phosphor Bronze strings combine our most popular acoustic alloy with an advanced corrosion resistance treatment on every string in the set, preserving the natural tone and feel of uncoated strings. Available for 6 and 12 String acoustic guitar ranging from extra light to medium gauges. Features XT strings feature an extended lifespan treatment on every string in the set, preserving the natural tone and feel of uncoated strings