Ernie Ball Earthwood Phosphor Bronze Acoustic Guitar Strings are made from 92% copper, 7.7% tin, 0.3% phosphorus wire wrapped around tin plated hex shaped steel core wire. These guitar strings have a light orange, gold colour and provide a mellow, ringing sound, with excellent clarity. Gauges .010 - .010, .014 - .014, .022w - .009, .030 - .012, .010 - .018p, .048 - .028