A new, patented design for enhanced play and longer life. The Martin Lifespan 2.0 Phosphor Bronze strings feature new technology that protects the core and wrap wire, to prevent corrosion. These Lifespan 2.0 strings include gauge 10-14-23-30-39-47. 
These Authentic Acoustic strings have been developed by Martin for two years. This is to ensure that they look, sound and feel better than ever before. Manufactured with copper, tin and phosphorous, Phosphor Bronze strings yield a dark and slightly warmer tone that 80/20 strings.