Martin MA550 Authentic Acoustic SP Phosphor Bronze Acoustic Guitar Strings -

At C.F. Martin & Co., they design their strings like they design  their guitars — with maximum performance, exacting tone, and playability  in mind. They know that musicians demand strings that will perform  onstage, in the studio, or wherever their music takes them. Martin  strings are designed to deliver excellent tone, clarity, and response  and are made from the highest-quality materials. Bizarre Guitar knows that  you take your choice in strings very seriously, so make the most out of  your next restringing and choose Martin acoustic guitar strings.