Pioneering Phosphor Bronze acoustic guitar strings are precision wound with phosphor bronze wrap wire over a high-carbon steel core, providing tonal versatility suitable for all acoustic styles and musical genres. This 09-45 Extra Light 12-String set is D'Addario's lightest gauge for 12-string acoustic guitar, providing easy playability while retaining adequate tone and projection for most playing situations. • MFSKU EJ41 • UPC 019954121204