Check the listing for details. Martin MA170 Authentic Acoustic Superior Performance 80/20 Bronze Guitar Strings. Condition: New. Listed at 20.99 USD. Quality 3-pack of Martin Acoustic Strings At C.F. Martin & Co., they design their strings like they design their guitars: with maximum performance, exacting tone, and playability in mind. Made from the highest-quality materials, Martin strings are designed to deliver excellent tone, clarity, and response wherever you perform. Martin Superior Performance strings feature their highest tensile-strength core wire with a tin plating on all six strings for enhanced corrosion resistance and the highest-quality wrap wiring Martin offers. Taken together, these features translate to incredible tone and amazing longevity. Sweetwater knows that you take your choice in strings seriously, so make the most out of your next restringing by choosing Martin acoustic guitar strings.