The MM1012 Retro 12-string acoustic guitar strings represent yet another quality, vintage-inspired set of strings in Martin’s Retro line. These strings harken back to the 1930s when nickel ruled the acoustic world. Made from Monel, a solid nickel/copper wrap, the MM1012s let your 12-string acoustic’s natural wood tone ring through with a full low end, a high-end snap, and a solid midrange. The proprietary wrap on the MM1012s is corrosion-resistant and impressively strong for long life and uncompromised tone.