Ernie Ball Earthwood 80/20 bronze medium acoustic guitar strings provide a crisp tone and pleasing overtones that acoustic guitarists crave. The 80-percent copper and 20-percent zinc wire is wrapped around a tin-plated steel core, producing a ringing sound with balanced lows, mids and highs. You'll enjoy playing complex chords and melodic lines as the strings respond with a clear, resonant voice. Whether you play fingerstyle or strum, these medium gauge strings handle it all. For acoustic guitarists seeking a warm, natural tone, Ernie Ball Earthwood strings deliver.