Ernie Ball Earthwood Extra Light Phosphor Bronze Acoustic Guitar Strings, 10-50 GaugeErnie Ball Earthwood Phosphor Bronze acoustic guitar strings are produced with an exclusive phosphor bronze wrap wire. Engineered to meet the demands of acoustic musicians, these concert quality strings provide deep, rich bass notes with clear bright trebles. Made with the finest and freshest raw materials, all Ernie Ball strings are hermetically sealed to ensure your strings stay as fresh as the day they were made. Gauges . 010 . 014 . 020w . 028 .