Gauges 9-13-22w-34 Ernie Ball 2067 Earthwood light mandolin strings are crafted from 80% copper, 20% zinc wire wrapped around hex shaped tin plated steel core wire. These popular strings provide a crisp, ringing sound with pleasing overtones. All Ernie Ball strings are precision manufactured to the highest standards and most exacting specs to assure consistency, optimum performance, and long life.