The Ernie Ball 2005 Earthwood 80/20 Bronze Acoustic Custom Medium 12.5–56 set is designed for acoustic players who want a balance of warmth projection and enhanced tonal complexity. The string set uses 80% copper and 20% zinc alloy wrap wire around a hex-shaped brass-plated steel core to deliver a crisp full sound with pleasing overtones.This custom medium gauge includes slightly thicker treble strings (.0125 and .0165) adding subtle tension for greater dynamic control without overloading the top end. The low strings (.024w .034 .046 .056) provide depth and clarity making the set ideal for both strummers and fingerstyle players looking for a stronger acoustic response.