Since D'Addario introduced Phosphor Bronze strings in 1974, they've been synonymous with warm, well-balanced tone. The XT coating delivers advanced corrosion resistance, while still retaining the warm tone and natural feel of the uncoated string. Beneath the coating, these XT baritone guitar strings are constructed with a NY Steel core, phosphor bronze wrap wire, and Fusion Twist technology, affording tonal versatility with added resilience. This 16-70 gauge baritone set is optimized for baritone acoustic guitars.