Martin's Authentic Acoustic strings truly have the performer in mind, and are engineered to stand up to the rigors of consistent and extensive use. At the core is Martin's highest tensile-strength core wire, tin-plate it on every string for more corrosion resistance. Combined with their highest quality wrap wire, these strings deliver consistently true tone that you can count on. They also offer incredible tuning stability, so you don't need to worry about those annoying tune-ups typically necessary between each song. String up your favorite acoustic, and just play.