Martin SP strings are designed with the performer in mind. Made with high tensile strength core wire and finished with our highest quality wrap wire, our SP line of strings stands up to rigorous practice and performance schedules to deliver consistent true tone that you can count on song after song. Martin SP strings are designed with the performer in mind. Made with high tensile strength core wire and finished with our highest quality wrap wire, our SP line of strings stands up to rigorous practice and performance schedules to deliver consistent true tone that you can count on song after song. Martin SP Phosphor Bronze strings are made with the highest quality bronzed steel core wire and phosphor bronze wrap wire. Medium .013 .017 .026 .035 .045 .056 181.1 MSP-3200
- Bronze alloy for brilliance and long life
- Gauges 13-17-26-35-45-56.
