Martin Lifespan SP Phosphor Bronze Acoustic Guitar Strings Guage 13-56

Martin SP Lifespan acoustic guitar strings are treated with Cleartone proprietary technology to bring you the longest possible string life without sacrificing tone or natural feel.
Martin SP Lifespan strings are designed to repel the oils and dirt that can deaden strings.
All six strings are treated to preserve the natural Martin SP sound and feel that players prefer. Phosphor Bronze strings are bright, but slightly warmer sound than 80/20 bronze when first put on the guitar.
They offer consistent tone over time.
Phosphor bronze has a copper/tin alloy, making them sound brighter than regular bronze strings.