Ernie Ball Earthwood Silk and Steel Regular 80/20 Bronze acoustic guitar strings are made with an 80/20 bronze alloy wrap, along with a layer of silk between the wrap and steel core. The silk produces a more mellow sound and makes the string feel more comfortable while reducing finger noise. Gauges .013, .017, .026, .034, .046, .056. Features: Layer of silk between the 80/20 wrap and core More mellow sound and comfortable feel Silk produces a more mellow sound and makes the string feel more comfortable