Developed in collaboration with John Mayer, Ernie Ball Earthwood Bell Bronze strings have been carefully crafted to meet John's exacting standards providing a new voice for your acoustic guitar. Inspired by alloys used traditionally for bells and cymbals, Ernie Ball's proprietary Bell Bronze acoustic guitar strings offer a richer, fuller sound than any other string in the E Ball catalog. • Big, BOLD sound and increased resonance with improved projection & sustain. • Gauges .013, .017, .026, .034, .046, .056 • MFSKU P02344 • UPC 749699118787