These Martin Darco D9600 Light/Heavy Gauge Nickel Wound strings are premium nickel guitar strings built to be tough and affordable so you can keep your axe screaming whether you want twang, snarl or bite. You can play more and pay less. Choose Darco to keep both rhythm and lead in your arsenal, from chugging lows to soaring highs. Gauge (Light/Heavy): 10-13-17-30-42-52