Martin LIfespan SP Medium Phosphor Bronze .013-.056 MSP7200SW

Martin SP Lifespan strings are the next level in studio performance. Treated for long life, they repel dirt, grit and other environmental elements that can quickly alter the sound of your strings. The treatment is so incredibly thin, you won't even know it's there. SP Lifespans are designed to last longer and sound better so you can play on! Martin SP Lifespan Phosphor Bronze strings are made with bronzed steel core wire and phosphor bronze wrap wire, then and all six strings are treated for long life.