Gauges 13-17-26-35-45-56.

Martin SP Studio/Performance Series strings are ideal live, in the studio, or wherever maximum string life is desired. The creation of these high-performance strings is a result of research done in cooperation with specialty steel producers. Due to the development of an industry-leading, ultrahigh-quality steel core, Martin SP strings resist breakage better than average strings. In addition, both the core wires and the plain strings are plated with a smooth, acoustic bronze finish. Though this golden bronze finish does enhance the beauty of your guitar, its purpose is much more functional”to prolong brightness, string life, and superior tonal quality to meet the high expectations of demanding musicians.