Crafted with a tin-plated hexagonal steel wire wrapped in an alloy wire comprised of 92% copper, 7.7% zinc, and .3% phosphorus, the Ernie Ball 2070 Earthwood Acoustic Bass Strings bring rich tone to the woody-minded four string set. Ranging in gauge from .045 to .110, these strings are marked by a mellow but resonant character that highlights the low-end.