Martin's next generation Lifespan 2.0 strings are engineered using a new, patented technology only available from Martin. This technology was developed to protect the core wire and the wrap wire to prevent corrosion without compromising tone - the single most important attribute of the guitar strings. Authentic Acoustic Lifespan 2.0 strings look better, sound better, and feel better, providing a smooth playing experience that reduces finger drag. We invested two years developing our next generation Lifespan 2.0 strings to ensure they will sound better, longer than any other extended-life string on the market. Available in 80/20 Bronze and 92/8 Phosphor Bronze. Martin Authentic Acoustic Lifespan® 2.0 strings offer next generation treatment for long life, great playability and feel, and superior reliability with authentic tone.