Instrument: 12-String Acoustic Guitar Gauge Range: 9 - 46 Gauges: 9 , 9 , 12 , 12 , 20 , 9 , 26 , 12 , 36 , 20 , 46 , 26 Wrap Material: Phosphor Bronze Construction: Round Wound Hex Core / Round Core Hex Core Ball End / Loop End: Ball End Coated / Non-Coated: Non Coated Ernie Ball Slinky Acoustics are produced with an exclusive phosphor bronze wrap wire (Made from 92% copper, 7.7% tin, 0.3% phosphorus wire). Engineered to meet the demands of acoustic musicians worldwide, these concert quality strings provide deep, rich bass notes with clear bright trebles. Ernie Ball Slinky Acoustics are played by The Counting Crows, The Edge, and Maroon 5 amongst many other touring musicians. Made with the finest and freshest raw materials, all Ernie Ball strings are hermetically sealed to ensure your strings stay as fresh as the day they were made. Gauge 2153 - 09 / 09 / 12 / 12 / 20w / 09 / 26w / 12 / 36w / 20 / 46w / 26w.