Light 6 string set for acoustic guitar from Retro series that brings back to life the original nickel acoustic string – the real deal – all the way from the 1930s. These strings offer a uniquely mellow, yet crisp, sound that allows the guitar’s natural tone woods to be heard, not overshadowed. They are crafted with tin-plated steel core wire and Monel, a solid nickel/copper wrap wire – not nickel-plated – meaning there is no chance for defects in the plating to allow for corrosion. Instead, Martin’s proprietary wrap wire is naturally corrosion resistant and it is incredibly strong. The sophisticated winding process in the making of the strings is employed, to control the coupling between the core and wrap wire to maximize intonation. Gauges: .012, .015, .025, .031, .041, .054.