Gauges 9-9ÿ 12-12ÿ 20w-9ÿ 26-12ÿ 36-20pÿ 46-26.Ernie Ball Earthwood 2010 Acoustic Guitar Strings are crafted from 80% copper, 20% zinc wire wrapped around hex shaped tin plated steel core wire. The most popular acoustic provides 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.