Martin Authentic Phos Bronze 12 String Treated Extra Light Acoustic Strings - MA500T

Next generation Martin® Authentic Acoustic® Lifespan® 2.0 strings are engineered using a new, patented anti-corrosion treatment only available from Martin. It protects the core and wrap wire to prevent corrosion without compromising tone or feel. 

Martin's  impeccable standards for acoustic guitar tone are embedded in our string design and precision manufacturing process. That’s why they make their own.