Ernie Ball 2065 Earthwood 80/20 Bronze Mandolin Medium Strings Gauges 10-14-24w-36. Ernie Ball 2065 Earthwood Medium 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.