A new patented design for enhanced play and longer life. The Martin Lifespan 2.0 80/20 Bronze strings feature new technology that protects the core and wrap wire to prevent corrosion. These Lifespan 2.0 strings include gauge 11-15-23-32-42-52. 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 80 percent copper and 20 percent zinc these acoustic guitar strings yield a bright and ringing tone. Features Set of 6 acoustic guitar strings Custom light gauge 11-52 Metal wrap wire composition of 80 copper and 20 zinc Lifespan 2.0 strings have new patented design Look sound and feel better than Martins previous strings Provides smooth playing experience with reduced finger drag Specifications Gauges: 11-15-23-32-42-52 Tension: 156.6