Product Information: Next generation Martin® Authentic Acoustic® Lifespan® 2.0 strings are engineered using a patented anti-corrosion treatment only available from Martin. It protects the core and wrap wire to prevent corrosion without compromising tone or feel. Our impeccable standards for acoustic guitar tone are embedded in our string design and precision manufacturing process. That’s why we make our own. Product Features: Warranty period: 12 Months 3-pack of strings designed by C.F. Martin & Co. to provide superior tone for your acoustic guitar Treated with Martin's Cleartone proprietary formula for longer life and great tone Highest-quality materials mean outstanding tone, response, and durability Strings subjected to Martin's rigorous premarket testing to ensure consistency and quality For more information and specifications, please refer to the manufacturer's website