These Ernie Ball Earthwood 80/20 Bronze Alloy Medium Acoustic Guitar Strings are manufactured in the USA to the highest standards. With a gauge of 13-56 these Earthwood strings provide bright and balanced tones with crisp and pleasing highs. These popular acoustic guitar strings are ideal for guitarists who enjoy a bright sparkling sound with excellent intonation. These 80/20 strings are precision wound from 80 copper and 20 zinc and they come as a 12 string set.