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. • MFSKU 41Y18MA540PK3