Martin Authentic SP Acoustic Guitar Strings, 6 String Set, Superior Performance with Authentic Tone, 80/20 Bronze, Extra Light Gauge (10-14-23-30-39-47), Tension 138.2, Martin Item MA170.

Martin Authentic Acoustic SP strings offer excellent tuning stability, corrosion resistance, and great playability. These strings are engineered with the performer in mind and they will always stand up to rigorous practice and performance schedules. It starts with highest tensile-strength core wire then tin-plate for added corrosion resistance.