Description Ernie Ball Earthwood 80/20 Bronze Medium 12-54 Acoustic Guitar String Set Ernie Ball Earthwood 80/20 Bronze Acoustic Guitar Strings are made from 80% copper, 20% zinc wire wrapped around hex shaped brass plated steel core wire. These acoustic guitar strings provide a crisp, ringing sound with pleasing overtones. Gauges .012, .016, .024w, .032, .044, .054 “I use these when I really need something to butter my biscuits if you know what I mean (and I know you don’t).”      – Christopher Kelley of The Axe Palace