D'Addario NBM11540 Nickel Bronze Mandolin Set, Custom Medium, 11.5-40 D'Addario's premium uncoated custom medium mandolin string set that provides a crisp and clear sound to accentuate the unique tone of your mandolin. NBM11540 delivers an ideal tone and the optimal blend of tight playing tension and strong projection. Loopend construction for universal fit. String Gauges: Plain Steel .0115, .016, Nickel Bronze Wound .026, .040