Gibson Coated 80/20 Bronze Acoustic Guitar Strings help draw out the true acoustic sound of your guitar. Wrapped with an 80% copper, 20% zinc alloy and coated very thinly with a proprietary polymer, these strings deliver bright and crisp tones while maintaining the perfect balance of authentic acoustic sound & playability. A favorite in the studio, Gibson Coated 80/20 Bronze Strings are ideal for all Gibson Acoustic body designs and all playing styles. Medium Gauge: .013 .017 .026 .035 .045 .056