A 6-pack of high-quality, long-lasting strings Ernie Ball 2002 Earthwood Acoustic Guitar Strings are crafted from 80% copper, 20% zinc wire wrapped around hex-shaped, tin-plated, steel core wire. Among the most popular acoustic guitar strings from Ernie Ball, they 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.Gauges 13-17-26-36-46-56...... A 6-pack of high-quality, long-lasting strings Ernie Ball 2002 Earthwood Acoustic Guitar Strings are crafted from 80% copper, 20% zinc wire wrapped around hex-shaped, tin-plated, steel core wire. Among the most popular acoustic guitar strings from Ernie Ball, they 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. Gauges 13-17-26-36-46-56.