(Item: 647139315164) Adamas 1919E Ovation Med.13-56 Acoustic Guitar String Set: Ovation Adamas 1919 Ovation Adamas 1919 A/StringsACOUSTIC GUITAR STRINGSMEDIUM: .013 .016 .025w .035 .047 .056Designed from the inside out for balanced performance in tone and feel, Adamas Phosphor Bronze wrap wire produces a rich, full sound with even tone throughout the harmonic range. Their Composite GaugingTM technique utilizes core and wrap wire of identical size so that neither part of the string dominates the various modes of string vibration. Thus, the strings vibrate more consistently and with greater amplitude to produce a sharper, more precise tone.