Martin Guitar Lifespan 2.0 MA140T, 80/20 Bronze, Treated Light-Gauge Acoustic StringsMartin Guitars Authentic Acoustic Lifespan 2. 0 Strings provide unrivaled quality, craftsmanship, and tone for your acoustic guitar. Designed to produce true, consistent tone, these extra light gauge strings provide excellent tuning stability and playability so your guitar can stand up to rigorous practice and performance schedules. Made from 80 20 bronze, these strings feature a patented anti corrosion treatment that protects the core and wrap wire