Ernie Ball Earthwood 80/20 Bronze Acoustic Guitar Strings are made from 80 percent copper, 20 percent zinc wire wrapped around a hex shaped brass plated steel core wire. These acoustic guitar strings provide a crisp, ringing sound with pleasing overtones. .011 .011, .015 .015, .024w .010, .030 .014, .042 .022w, .052 .028. Features: Natural feel and tone Element shield packaging prolongs string life and keeps strings fresh Featuring the finest and freshest materials